Category: journal of personal science

Journal of Personal Science: Omega-3, Nursing a Baby and Postpartum Depression (Part 1 of 2)

Seth Roberts14 Comments

by Allan Folz

My wife had moderately severe postpartum depression (PPD) after the birth of our first child, a boy, in 2004. The depression lifted at the same time the nursing stopped, when he was about two years old. The pregnancy itself was without major or even minor problems so the depression was a big surprise. It was frustrating because nothing we did to alleviate it actually helped.

With our second child, born in 2007, for the whole pregnancy we were worried she would experience it again. Thankfully she did not. There were a couple of differences between the two pregnancies. Our first baby was a boy and born with a complication during delivery. The placenta did not release. This caused to be transferred to a hospital, as it was a home birth. At the hospital she was given two units of whole blood. Our second baby was a girl, also born at home, and this time with no issues.

Her third pregnancy was in 2010 and this is where the story begins.

A couple months before she became pregnant, I had discovered paleo dieting following a link to Richard Nikoley’s blog. I read about his experience and followed links to other sites in the paleosphere. The diet, the rationale behind it, and the numerous reports of other people having their health remarkably improved by it really resonated with me, so we adopted a lower-carb, paleo-style diet.

We didn’t have health problems that we were trying to correct for ourselves or a particular need to lose weight, outside of a few pounds for my wife relative to how much she weighed prior to her first pregnancy some six years before. However, I’ve always had an interest in health, medicine, and how the body functions. I even considered becoming an M.D. back in my undergrad days and minored in biology alongside my major in electrical engineering. I have a strong skepticism towards experts and what is the conventional wisdom in mainstream media sources. I think that’s why I almost immediately found Seth’s blog so intriguing, he questions the conventional wisdom and pushes people to take personal responsibility over their health and well-being. So, we were on a low to moderate carb diet, but weren’t fanatical about it. I remember that after my wife’s first visit with her midwives they were concerned by the ketones in her urine and strongly suggested she start eating more complex carbs. She followed their advice to be conservative. We were also supplementing Vitamin D and a little fish oil (a Mega-EPA omega-3 supplement). She was averaging 5K IU of Vitamin D a day, but only about one, 1 gram capsule once or twice a week of the fish oil. All in all, not much fish oil as I wasn’t sure how much was really necessary for people otherwise eating traditionally healthy, home-cooked meals, and I’m very skeptical of the diet supplement industry.

Late in the third trimester she started experiencing some moodiness. By itself, it probably would not have seemed atypical for a woman in her third trimester, but with my wife’s history we were far more sensitive to it and quick to take notice. Paying close attention (and long before discovering Seth’s blogging on self-experimentation), I eventually realized the moodiness happened when we’d skipped taking fish oils mid-week. If she didn’t take any mid-week, by Saturday it was very noticeable that her mood was on the short-tempered side. Once I noticed the connection, and without telling her what I was doing (i.e. single-blind), I’d deliberately skip the mid-week dose one week and note her weekend temper and mood. The following week I’d be sure she took a capsule mid-week. Next week back to skipping. Then, just to be sure, I had her double-dose one week. The double-dose had her in the best mood of all.

At first I was amazed. It was so neat, so mechanical — like flipping a switch. But it occurred to me that if two capsules in a week vs. one was enough to noticeably change her mood then she was obviously deficient as every mg was being put to use with no spare capacity in her system. I wondered if her body was scavenging omega-3 from her own brain for the developing fetus. That was a sobering thought. After that she went to supplementing daily and had no mood issues throughout the rest of the pregnancy or while breast feeding. She did have some of the typical “baby blues” that set in at the three day mark, but they did not last long. Also, she had good days and bad days, like anyone would. I’d say the omega-3 returned her to her normal bearing, irrespective of the demands of pregnancy and nursing.

There is zero doubt in my mind that omega 3 helped both my wife deal with a severe and yet all too stereotypical mental health problem. I’m a pretty sharp, pretty well-read guy who’s always had an interest in biology and medicine. After the experience with our son’s weaning, I wondered if nursing could cause or complicate PPD.

Seven years ago, when my wife was pregnant for the second time, I had searched the web for material related to those two (nursing and PPD) and came up empty-handed. I know I’ve never read something dealing with those two in mainstream outlets because it’s the type of thing I would mentally file away for future reference if the situation ever came up. It seemed like I was the only one willing to consider there might be a connection between them. Diet suggestions for nursing mothers are full of the usual bromides about getting enough complex carbs, fiber, and protein. Search engine auto-completes on “postpartum depression” don’t offer “omega-3” or “diet” anywhere in the top 10. You have to type the first two letters of each before they pop-up as auto-complete options. Today, the first hit for “postpartum depression diet” (I use Bing) is https://www.postpartum-living.com/depression-diet.html, which makes absolutely no mention of fats or lipids. It mentions vitamins, of course, but, incredibly, nothing specific.

During the two years my wife had PPD after her first pregnancy, no one suggested omega-3. At the time, I attributed her PPD to the delivery complications and the blood transfusion. I knew that depression is well-known among heart-attack survivors and IVF recipients, and, in my opinion, IVF is a pretty severe complication. Among the health professionals she saw about her PPD, the only thing the MD did was give her a prescription for Prozac or something similar, which she didn’t use because, well, of course — she was nursing. Had she quit nursing to take the prescription we would have attributed the improvement to the drug when it actually came from ceasing nursing. The naturopathic practitioners — she saw two different ones — gave her B-12 shots, SAM-e, melatonin, and a bunch of useless diet advice that one could read at all the usual places. The B-12 was good for a 24-48 hour energy boost. Other than that, none of them made the slightest difference.

Part 2, about using omega-3 to treat ADHD, will appear tomorrow. Allan Folz is a software developer in Portland, Oregon. He recently co-founded Edison Gauss Publishing, a software house that makes academically rigorous educational apps for children in grades K-8. Their apps are suitable both classroom and home use, and have proven to be particularly popular among homeschoolers that appreciate a traditional approach to practicing math.

Journal of Personal Science: Effect of Meditation on Math Speed

Seth Roberts5 Comments

by Peter Lewis

Background

I’ve been practicing meditation on and off for years. It doesn’t interest me in a spiritual sense; I do it because I think it improves my mental function. However, what I’ve read suggests there isn’t a lot of evidence to support that. For example, John Horgan in Scientific American:

Meditation reportedly reduces stress, anxiety and depression, but it has been linked to increased negative emotions, too. Some studies indicate that meditation makes you hyper-sensitive to external stimuli; others reveal the opposite effect. Brain scans do not yield consistent results, either. For every report of heightened neural activity in the frontal cortex and decreased activity in the left parietal lobe, there exists a contrary result.

From a 2007 meta-analysis of 800+ studies:

Most clinical trials on meditation practices are generally characterized by poor methodological quality with significant threats to validity in every major quality domain assessed.

Most of this research asked questions different than mine. The studies used physical measures like blood pressure, studied complex states like depression and stress, or isolated, low-level “executive functions” like working memory. My question was simpler: Is mediation making me smarter? “Smarter” is a pretty complex thing, so I wanted to start with a broad, intuitive measure. There’s a free app called Math Workout (Android, iPhone) that I’ve been using for years. It has a feature called World Challenge that’s similar to what Seth developed to test his own brain function: it gives you fifty arithmetic problems and measures how fast you solve them. Your time is compared to all other users in the world that day. This competitive element has kept me using it regularly, even though I had no need for better math skills.

Study Design

I only had about a month, so I decided on a 24-day experiment.

Measurement. Every day for the whole experiment, I completed at least four trials with Math Workout: three successive ones in the morning, within an hour of waking up, and at least one later in the day. For each trial, I recorded my time, number of errors and the time of day. Math Workout problems range from 2+2 to squares and roots. The first ten or so are always quite easy and they get more difficult after that, but this seems to be a fixed progression, unrelated to your performance. Examples of difficult problems are 3.7 + 7.3, 93 + 18, 14 * 7, and 12² + √9. If you make a mistake, the screen flashes and you have to try again on the same problem until you get it right. As soon as you answer a problem correctly, the next one appears.

Treatment. I used an ABA design. For the first seven days, I just did the math, with no meditation. (I hadn’t been meditating at all during the 3-4 weeks before the start of the experiment.) For the next ten days, I meditated for at least ten minutes every morning within an hour of waking, and did the three successive math trials immediately afterward. I did a simple breath-counting meditation, similar to what’s described here. The recorded meditations that I gave the other participants were based on Jon Kabat-Zinn’s Mindfulness Based Stress Reduction program and also focused on awareness of breathing, though without the counting element. The final seven days were a second baseline period, with no meditation.

Before beginning, I posted about this experiment on Facebook, and I was pleasantly surprised to get eleven other volunteers who were willing to follow the same protocol and share their data with me. I set up online spreadsheets for each participant where they could enter their results. I also emailed them a guided ten-minute meditation in mp3 format. It was a fairly simple breathing meditation, secular and non-denominational.

Results

Meditation had a small positive effect. During the meditation period, my average time to correctly answer 50 problems was 75 seconds, compared to 81 during the first baseline — a drop of 7% — and the times also dropped slightly over the ten days (slope of trendline: -0.6 seconds/day). When I stopped meditating, my times trended sharply back up (slope: 1.0 seconds/day) to an average of 78 seconds during the second baseline period. These trends suggest that the effect of meditation increased with time, which is in line with what most meditaters would tell you: the longer you do it consistently, the better it works. My error rates were more flat — from 2.1 errors per 50 correct answers in the first baseline period, to 2.2 during the meditation period and 2.5 during the second baseline — and did not display the same internal trends.

(click on the graph for a larger version)

med_PL_small

Of the other eleven subjects, six of them stuck with the experiment till the end. Their data was messier, because they were new to the app and there’s a big practice effect. Because of this, I was less focused on finding a drop from the first control period to the meditation (which you’d expect anyway from practice) and looking more for an increase in times in the second control period (which you wouldn’t expect to see unless the meditation had been helping).

Taking that into account, three of the six subjects seemed to me to display a similar positive effect to mine. Two I’d call inconclusive, and one showed a clear negative effect. (Here is the data for these other subjects.)

What I Learned

I found these results encouraging. Like Seth, I take this kind of basic math exercise to be a good proxy for general brain function. Anything that makes me better at it is likely to also improve my performance on other mental tasks. As I mentioned above, I’ve been using this particular app for years, and my times plateaued long ago, so finding a new factor that produces a noticeable difference is impressive. An obvious concern is that I was trying harder on the days that I meditated. Since it’s impossible to “blind” subjects as to whether they’ve meditated or not, I can’t think of a perfect way to correct for this. If meditation does make me faster at math, what are the mechanisms? For example, does it improve my speed at processing arithmetic problems, or my speed of recall at the ones that I knew from memory (e.g. times tables), or my decisiveness once I think I have an answer? It felt like the biggest factor was better focus. I wasn’t solving the problems faster so much as cutting down on the fractional seconds of distraction between them.

Improvements

It would have helped to have a longer first control period, as Seth and others advised me before I began. I was scheduled to present my results at this conference and at the time it was only a month away, so I decided to make the best of the time I had. Next time I’ll have a three- or four-week baseline period, especially if I’m including subjects who haven’t meditated before. The single biggest improvement would be to recruit non-meditators to follow the same protocol. Most of the other volunteers, like me, were interested because they were already positively disposed towards meditation as a daily habit. I don’t think they liked the idea of baseline periods when they couldn’t meditate, and this probably contributed to the dropout rate. (If I’d tried to put any of them in a baseline group that never meditated at all and just did math, I doubt any of that group would have finished.) It might be easier to recruit people who already use this app (or other math games) and get them to meditate than vice versa. That would also reduce the practice effect problem, and the effects of meditation might be stronger in people who are doing it for the first time. More difficult math problems might be a more sensitive measure, since I wouldn’t be answering them from memory. Nothing super-complex, just two- or three-digit numbers (253 + 178).

I’m planning to repeat this experiment myself at some point, and I’m also interested in aggregating data from others who do something similar, either in sync with me as above, or on your own timeline and protocol. I’d also appreciate suggestions for how to improve the experimental design.

Comment by Seth

The easiest way to improve this experiment would be to have longer phases. Usually you should run a phase until your measure stops changing and you have collected plenty of data during a steady state. (What “plenty of data” is depends on the strength of the treatment you are studying. Plenty of data might be 5 points or 20 points.) If it isn’t clear how long it will take to reach steady state, deciding in advance the length of a phase is not a good idea.

Another way to improve this experiment would be to do statistical tests that generate p values; this would give a better indication of the strength of the evidence. Because this experiment didn’t reach steady states, the best tests are complicated (e.g., comparison of slopes of fitted lines). With steady-state data, these tests are simple (e.g., comparison of means).

If you are sophisticated at statistics, you could look for a time-of-day effect (are tests later in the day faster?), a day-of-week effect, and so on. If these effects exist, their removal would make the experiment more sensitive. In my brain-function experiments, I use a small number of problems so that I can adjust for problem difficulty. That isn’t possible here.

These comments should not get in the way of noticing that the experiment answered the question Peter wanted to answer. I would follow up these results by studying similar treatments: listening to music for 10 minutes, sitting quietly for 10 minutes, and so on. To learn more about why meditation has an effect. The better you understand that, the better you can use it (make the effect larger, more convenient, and so on).

 

Journal of Personal Science: One Child’s Autism Eliminated by Removal of Glutamate From Her Diet

Seth Roberts7 Comments

by Katherine Reid

I am a mother of five children. I live in Fremont, California. In 2009, my youngest child, who was three, was diagnosed with autism. The diagnosis came from her social and communication impairment and highly repetitive behavior. She did not play with other children. She had no imaginary play. She made no eye contact with anyone. She had no spontaneous language. She did not understand questions. Her language was restricted to repeating what she heard (echolalia). In other words, she didn’t use language to communicate. She could stack blocks for hours. She would line up toys and have a meltdown if you moved a toy out of line. Everything had to be according to her rules or she was in chaos. She had highly repetitive routines that would escalate into unrest or panic. For example, she would go to wash her hands, turn the water on, turn the water off, turn the water on, and so on. Each time through the routine she would get more upset that she couldn’t stop. These loop-like routines might last hours, typically ending because of exhaustion from crying. She also had episodes of absence (blank stares) that lasted 15-30 seconds.

My husband and I tried a number of popular therapies. We tried Applied Behavioral Analysis (ABA) for 3 months. She got worse; her loop-like routines occurred more frequently. We tried speech therapy for 6 months. It increased her vocabulary, but did not improve her communication in other ways. The third therapy we tried was auditory integration training. We did the full series twice, which took a total of 3 months. There was no improvement. Then she started going to a special-needs school, where each student is given an individualized program. At this point, she was 3.5 years old.

Around the same time that she started the new school, we started changing her diet. I had been looking at nutritional deficiencies associated with autism. As a result, we added green veggie smoothies (for example, kale, cucumber, cilantro, nuts, seeds, fruits, it varied with the season) to her diet, supplemented with a multivitamin, magnesium, B complex, Vitamin D3, Omega 3′s (EPA and DHA) and probiotic blends (a mix of pills from different companies, such as New Chapter and MegaFoods). Within three days, she began to look people in the eye and began responding to her name. Before the autism diagnosis, we had taken her for a hearing test, because of her lack of response to her name.

This encouraged us to think that diet was important. We eliminated gluten and casein (dairy) from her diet. Many parents had seen improvement after they made this change. These changes were often not large enough to make the children no longer autistic, but they did improve. Our daughter’s response was similar. Her social and communication skills improved, but she was still about a year behind her peers. She still had long outbursts and meltdowns. We were sure it was the new diet, not the new school, that caused the improvement because several times she had eaten gluten or casein at school by accident (e.g., pizza) and her language and behavior regressed. This happened about ten times. Twenty-four hours after these exposures, she was considerably worse. She wouldn’t be able to articulate words and her language comprehension decreased. She also became much more emotional and picky (e.g., had to take a certain route home). The regression lasted about five days.

These improvements encouraged me to read more about diet and autism. I read a few clinical studies – there were hardly any. On blogs, I read about parents’ experiences. On one blog – I can’t remember which one — I read a comment from a parent that he found that his son benefited from removing gluten and casein, and, importantly, MSG made his son worse. What idiot feeds his child MSG? I thought. I was wrong.

I have a Ph.D. in biochemistry, with an emphasis in protein chemistry, from UC Santa Cruz. I have spent 20 years conducting research and development on proteins for therapeutics and molecular diagnostic applications. Proteins are made of amino acids, the most abundant of which is glutamic acid. When a protein breaks down, glutamic acid is released. I discovered that I had been feeding my daughter plenty of glutamate. I started researching connections between glutamate and autism and convinced myself it was plausible that too much glutamate caused behaviors associated with autism, as well as other brain disorders. Suddenly I understood why removal of gluten and casein might help. Both proteins have a high glutamate content (= a large fraction of their amino acids are glutamic acid). Common types of food processing break down these proteins. For example, fermentation, ultra-pasteurization, adding acid (such as lemon juice), and adding enzymes (e.g., when making cheese) all create free glutamate.

I started looking into food labels. Glutamate can be hidden in many ways, I learned. For example, “natural flavor” may be up to 60% glutamic acid. Perhaps my daughter had a predisposition to glutamate sensitivity; my research revealed that many of us do. There are glutamate receptors all over the body, including the brain. For example, glutamate receptors in the pancreas regulate insulin secretion. To reduce the amount of glutamate in her food, I tried to remove all processed proteins from her diet. This wasn’t simple. Apple juice may have “natural flavors”. Toothpaste may have glutamate. Our new diet mainly consisted of organic vegetables, fruits, seeds, nuts, meat, quinoa, and rice. We stayed away from any product with processed soy, corn, or wheat (because of the processed protein). Corn on the cob or edamame was fine because they aren’t processed.

This was a huge shift in the family diet and was met with protest. My husband was hesitant because the advice from a team of neurologists had been to try behavioral therapy again. (ABA is one type of behavioral therapy.) They thought a better therapist might help. That was their main advice. They told us they hadn’t seen gluten-and-casein-free diets produce improvement.

In May 2010, we made the big dietary changes. After we started the new diet, my daughter never again had a meltdown. She had had one the previous week. About a month later, at the end of the school year, we were contacted by the special-needs school. They said she had improved so much that she should go to a mainstream pre-school. At this point she was almost four. Her language and social skills quickly caught up with her peers. Of my five children, she is the most social and outgoing. Today, at 6 years old, she attends a public school kindergarten. At a September 2012 parent-teacher conference, her kindergarten teacher was shocked to find out that she had been previously diagnosed as autistic.

I decided to make it my mission to educate and raise awareness of the amount of free glutamate in our food and the health ailments associated with it. The name of my mission is Unblind My Mind. More information can be found at unblindmymind.org.

Katie spoke about this at the first Make Yourself Healthy Meetup.

Journal of Personal Science: Xylitol Cures Lichen Planus and Geographic Tongue

Seth Roberts8 Comments

Xylitol Improves Lichen Planus and Geographic Tongue

by Evelyn M., Westchester County, NY

Background

In my forties — I am now 75 — my gums started to bother me. Newly-returned to the United States from Iran, I searched for a good dentist. The first one told me to get a cap on a tooth with a small chip. That was no help. A colleague recommended a specialist in gum problems. The specialist advised “scaling,” which didn’t help. Then he said I was not cleaning my teeth well enough. He put a substance on my teeth to reveal incomplete cleaning and was flummoxed when he could find no evidence of bad brushing or flossing. I gave up trying to solve my gum problem.

When I was about 50, a “crisis tooth” (a molar on the upper right) forced me to see a dentist. I found a very good dentist, sensible and conservative in approach. After the problem tooth was removed, he turned to the overall condition of my mouth. I told him about the gum treatments I’d had. Then he showed me an x-ray that revealed an abscess under the root of a tooth on the lower right hand side. That tooth didn’t hurt, and looked OK, but was leaking pus into the gum, inflaming the entire lower right hand side of my gums. The gum specialist had missed it completely. After that tooth was removed, and the surrounding area healed, my gums were fine for many years.

Two years ago, I developed a condition called lichen planus. The entire inside of my mouth was inflamed and swollen — gums, tongue, the inside of my cheeks, all of it. I could not brush my teeth or eat anything except the blandest of foods. I also had a metallic taste in my mouth. It was torture.

After diagnosing the condition (“you have lichen planus”), my dentist sent me to an oral pathologist. The pathologist said there was no cure that he could guarantee and gave me two prescription drugs — one to treat problems caused by fungi, the other to deal with bacteria. Neither helped. I confirmed on the web what the dentist and the oral pathologist had said.

Concluding that medical science couldn’t help, I starting searching the web for other suggestions. I found Seth Roberts’s blog, which suggested taking flaxseed oil to improve gums. I tried it. My psoriasis improved but the lichen planus remained.

Source of Idea

In November 2011, the Drudge Report led me to an announcement that UCLA scientists were working on a mouthwash to prevent cavities. A comment said: “Xylitol is a plant sugar that kills s[treptococcus] mutans, and has been around for years as a toothpaste, mouthwash and gum. This is not new at all. Regular use of xylitol does all this, is cheap, and is NOT patentable. So, UCLA, this is nonsense.”

I found a wealth of data on the web about xylitol, mainly research from Finland. The evidence showed that it killed bacteria that cause tooth decay and helped re-mineralize decayed teeth. The reports often mentioned that general oral health had improved in patients using xylitol. I decided to try it.

Method

Most xylitol research has been done using gum that children chew after meals three or four times a day. I do not like to chew gum. I found other studies showing that taking a quarter to a half a teaspoon of the sugar (made from birch bark) four times a day is equally effective. I put the xylitol in my mouth, it melts, I swish it around my mouth until the saliva that it produces is quite extensive (60-90 seconds) and swallow it.

Results

I started taking xylitol more than a year ago. After six weeks, the metallic taste was gone and my inner cheeks were noticeably less inflamed. After three months it was clear that my tongue was improving. Now I am sure that the lichen planus is in remission.

My most recent dentist visit was six months ago [October 2012], after I’d been using xylitol for ten months. My dentist and hygienist were astounded. They had been expecting the lichen planus to look the same as when they had seen it before (one year earlier). By then, however, my mouth had healed substantially.

That wasn’t the only improvement. I’d always had what dentists call geographic tongue– deep fissures that make a pattern on the surface of the tongue. It never bothered me. I never noticed it until a dental hygienist pointed it out to me (in horror!). I went from having a tongue full of fissures and “ruffled” around the edges to a tongue that was completely healed and looked better than it had in many years. My dentist could still find some of the lace-like effects that lichen planus produces on the inside of my cheeks. The geographic tongue is now [March 2013] completely gone, as is all the plaque on my teeth, the redness of my gums, and the soreness and inflammation I had experienced from the lichen planus on the inside of my cheeks, my hard and soft palate, and uvula.

Discussion

When I told my dentist I was using xylitol, he knew what it was and was happy to see the improvement, but it had never occurred to him to suggest I use it. It is not a regular dental technique. I continue to use it, keeping jars of xylitol next to the kitchen stove and the computer screen (my two favorite haunts!) so that it is always at hand.

At the turn of the year (2012 to 2013) I emailed friends and family encouraging them to try xylitol. One friend started using xylitol by the end of January and in March told me about her progress. She has already noticed a great improvement in her gums. She said that she hadn’t been perfect in dosing herself, sometimes forgetting a day, often only using it three times a day instead of four or five, but since she now had evidence that it actually helps, she was determined to take it more religiously. She bought xylitol gum for her children, putting xylitol mints in their lunch boxes.

More Information

Controversies around xylitol.

Role of Xylitol in Oral Health (video)

Xylitol and dental caries

Sugar alcohols, caries incidence and remineralization of caries lesions: A literature review

Summary of xylitol research

Journal of Personal Science: How Much Salt Should I Eat?

Seth Roberts11 Comments

by Greg Pomerantz

The Journal of Personal Science, suggested by Tom and encouraged by Bryan Castañeda, will contain articles about using science to help yourself. This is the first one. It previously appeared on Greg’s blog. If you have written something or plan to write something or are thinking about writing something that might be included, please let me know. — Seth

I spent a few weeks this summer conducting a self-experiment on salt sensitivity and blood pressure. The experiment included a three week phase on a low carb whole foods diet with no added salt, followed by a moderately extreme salt loading phase. This post is a summary of my results.

I learned a lot from the experiment and came out of it with at least one bit of useful information. Will I try to restrict salt in my diet? No, I don’t think salt restriction can work for me. From now on I will ensure that I get sufficient salt on a daily basis.

Summary

These are the main points I learned during the experiment, from most to least interesting.

1. Salt restriction caused impaired thermoregulation. In hot weather, my cardiovascular system was not able to sufficiently lower my body temperature. This resulted in an elevated heart rate and hypethermia (up to 101.5 degrees in one instance). This can be dangerous, so be careful if you try this at home.

2. No clinically meaningful change in blood pressure. Systolic pressure was unchanged, though salt loading may have caused a small rise in diastolic pressure. This does not rule out long term negative effects from chronic salt loading (see discussion below), but it does show that, as previously discussed, my kidneys seem to basically work and can regulate my blood pressure through the maintenance of fluid and electrolyte balance in response to changes in my sodium intake.
3. Salt reduction may increase susceptibility to skin infections. Three days into the salt restriction phase, I came down with what was probably a staph infection in my right eyelid. This responded to antibiotics but it came back once I went off them. Since adding back salt I have had no problems with skin infections and no more antibiotics.
4. Possible strength loss. I did not perform well in the gym on my usual strength training program.
5. My taste for salt adapts quickly to restriction and loading. I experienced no cravings even when my sodium intake was too low. I can’t just “listen to my body”. Likewise, while the salt loading phase was difficult for the first two or three days, my taste rapidly adjusted to the added salt.
6. Bodyweight changes. I experienced substantial changes in body fluid levels (e.g. 6 pound weight gain within two hours of the transition from the salt restriction to the salt loading phase).

Conclusion: A low carb paleo diet must include added salt (for me). Can others do without? Perhaps, and some scientists such as Loren Cordain and Tim Noakes (e.g. this podcast episode 18 at 1:03:50) seem to think they can. Skip ahead to read my further musings on this question.

Study Design

The experiment had three phases. First, I did a one week lead-in phase (phase I) where I made no changes to diet or salt consumption. The purpose of phase I was to establish a blood pressure baseline through daily morning measurements (see Measurement Methods below).

This was followed by a three-week sodium restricted phase (phase II) during which I did not add any salt to my food. In addition, during phase II only, I avoided naturally salty foods such as shellfish. My sodium intake during phase II was limited to the sodium in the foods I was eating. Note however that there were one or two restaurant meals per week during this time where I was not able to strictly control for added salt. Sodium consumption on phase II was estimated to be between 800mg and 1000mg per day. phase II was originally scheduled for two weeks, but was extended due to the aforementioned infection and antibiotic use.

Finally, phase III was a salt-loading phase during which I added an additional 5 grams of sodium to my diet, for a total of nearly 6 grams of sodium per day including the sodium naturally occurring in my food. The supplemental salt during phase III consisted of hand harvested French Celtic sea salt (Eden Foods, Inc.) and was measured daily on an AMW-1000 digital scale. Because the Eden French Celtic sea salt is approximately 1/3 sodium by weight according to the label, the 5 grams of supplemental sodium per day was provided by approximately 15 grams of sea salt. Note that different varieties of salt will contain different percentages of sodium by weight. Sea salts vary significantly due to variations in residual water content (not, as commonly assumed, by the presence of other minerals). Please consult the label or a friendly analytical chemist for guidance.

The diet throughout this experiment consisted of meat, fish, eggs, coconut oil, butter, and non-starchy vegetables. In addition, I typically consumed a banana, an ounce (28g) of almonds and a bit of dark chocolate each day. Potassium intake was fairly consistent at around 4 g/day. Table 1 shows a typical day’s macronutrient intake. Given the macronutrient ratio, I believe it is likely that the diet was ketogenic.

Table 1. Approximate daily macronutrient intake.

Macronutrient
grams
 calories percent (calories)
Carbohydrate
50
 200 6.6%
Protein 155 620 20.5%
Fat 245 2205 72.9%
Total 3025
100%

 

Measurement Methods

I measured blood pressure daily first thing each morning while seated, with the cuff of an Omron HEM-711 placed on the left upper arm over the brachial artery. I followed guidelines described by Agena et al (see Chart 2 of the linked paper). Each day’s blood pressure value was determined by averaging the first three measurements taken that morning.

My first measurement of the day was typically higher than the average of the second and third measurements (systolic: +5, diastolic: +4, average over all three phases). This is referred to as the “alarm reaction” and is related to the more commonly known “white coat syndrome”, where the presence of a doctor elicits a stress response and therefore an innacurately high blood pressure reading. My alarm reaction seems to be due to the fact that I get slightly stressed out about seeing what my blood pressure is, even when I measure it myself. Therefore I experience a slight rise in blood pressure while waiting to see the first reading each day. I kept all three readings for this experiment. My “true” normal blood pressure is on average slightly lower than these results which include the first “alarm” reading.

Results

I summarized my qualitative findings in the executive summary above. If you skipped that because you are not an executive, you can go back and read it now. Below are graphs showing my blood pressure and bodyweight during the three phases.

Figure 1: Possible mild elevation in diastolic blood pressure during the salt loading phase. Each point is the average of the three morning blood pressure readings for the day. Red = phase I, green = phase II, blue = phase III. Curves from ggplot2 “geom_smooth()” using default parameters.

 

Figure 2. No change in systolic blood pressure.

 

Figure 3: Bodyweight.

Figure 3 shows my daily bodyweight, measured each morning before consumption of any food or fluids. Note that my previous health goal (the 415 deadlift) involved an intentional increase in bodyweight and therefore significant excess calorie consumption. My current diet is lower in calories and Figure 3 therefore should show a long term downward trend in bodyweight.

Salt restriction clearly resulted in a rapid decrease in bodyweight over the first few days of phase II. There appears to be a stabilization towards the end of the salt restricted phase. The salt loading in phase III produced a very large initial weight gain, followed again by stabilization around the same level seen at the end of the salt restriction phase. As salt is primarily stored in bones and extracellular fluids, an increase in salt would be expected to correspond to an increase in extracellular fluid (since the body’s bone mass should change slowly). The bodyweight changes shown in Figure 3 therefore reflect changes in extracellular fluid levels. While salt loading at the levels used in phase III produced a large acute change in body fluids, this was restored to normal over approximately 5 days.

Since my extracellular fluid volume was evidently restored within 5 days, it is not surprising that salt loading had no significant effect on my blood pressure. What is somewhat surprising was that there was no evidence of a temporary increase in blood pressure during the few days in which my extracellular fluid volume was in fact elevated. This suggests that there is an additional regulatory element working to restore blood pressure homeostasis at a shorter time scale than the dominant kidney-fluid mechanism previously discussed on the blog here.

Thanks to Mako Hill for guidance with ggplot2, without which these plots would look less nice.

Discussion

This experiment demonstrated to me that a low carb paleo diet with no added salt is potentially dangerous for me. Impaired thermoregulation is a big deal and would have been a life-threatening issue if I had to hunt for my food in a hot climate. Not only was my body temperature elevated in warm weather, but my pulse was elevated as well, suggesting my cardiovascular system was unable to restore my body temperature to normal. I’m clearly not salt sensitive, and I do not function well with a low salt diet. However, genetic studies suggest the ancestral human genotype is associated with high levels of salt sensitivity and ability to function with very low sodium intakes. How did humans evolve these traits? And why don’t I seem to have them?

A Faustian Kidney Bargain

Susumo Watanabe has proposed in interesting hypothesis about the evolution of sodium metabolism in hominids. The theory is laid out in a 2002 paper called “ Uric Acid, Hominid Evolution, and the Pathogenesis of Salit-Sensitivity,” published in the journal Hypertension. It goes something like this. At some point during the evolution of our common ancestor with gorillas and chimpanzees, a series of mutations inactivated the gene for urate oxidase, an enzyme that breaks down uric acid. As a consequence, we have much higher blood levels of uric acid than other mammals. These mutations seem to have occurred between 24 and 8 million years ago, during the miocene, when our ancestors were believed to be subsisting primarily on fruits and leaves. This diet would have been exceptionally low in sodium. Since there is evidence of multiple independent mutations in this gene in multiple primate lineages, it is thought that mutations deactivating urate oxidase were strongly selected.

In rats, uric acid raises blood pressure acutely, but also causes renal vascular disease via renin/angiotensin systems. This over time makes the rats more salt sensitive. If there is very little salt available, salt sensitivity can be a good thing. Watanabe argues that, where salt is scarce, high uric acid is beneficial (via multiple pathways) for preventing blood pressure from going too low.

In addition to causing kidney disease, high uric acid causes other problems, like gout, and is associated with heart disease. So this looks like an engineering tradeoff with a number of downsides, but some benefits in the context of a miocene diet that was even lower in sodium than the lowest current estimates for paleolithic diets. The organism with this adaptation is supposed to partially destroy its kidneys on purpose in order to maintain sufficiently high blood pressure. This miocene environment is long gone. However, it is much easier to break a gene than to put it back together. Our urate oxidase gene has been broken more than once and it would take quite a long time to fix it.

It’s kind of a crazy theory. I’m not sure I believe it but it is interesting to think about.

Some Hypotheses

During this experiment, I was eating almost exclusively meat, fish (often with bones), eggs and vegetables, plus added calories from butter, coconut oil and olive oil. The diet was grain, legume and dairy free and, as mentioned, possibly ketogenic. This would be considered by many online diet and health personalities to be a good low carb paleo diet, even though of course processed fats like butter and coconut oil are not Paleolithic foods.

So I want to discuss a few possible ways to resolve the apparent impossibility of eating this way without added salt.

Hypothesis 1: Low Carb, Low Crab, or Low Salt: choose any two

I have been eating a low carb diet, and my experiment suggests that, in that context, low salt is not a good idea. It is possible that a healthy human diet can be either low in carbohydrates or low in salt, but not both.

A great deal of evidence suggests that ketosis was not the norm for our paleolithic ancestors (see e.g. Kuipers et. al. 2012 for a thorough review of paleolithic diet research). In fact it would have been quite a struggle for me to eat this sort of macronutrient ratio without modern refined fats such as butter and coconut oil. Or ready access to marine mammal blubber (but then again the Inuit are not my paleolithic ancestors).

In contrast to the online paleo diet scene, most low carb diet advocates seem to line up behind the recommendation for ample supplementary salt. My result accord with that clinical experience. Low carbohydrate diets are usually said to have a diuretic effect in this community, at least in the initial stages (e.g. M.R. Eades, Jenny Ruhl). It is possible that my problems were caused by the interaction between diet-induced ketosis and salt restriction, and I would have done just fine without salt if I had some more carbohydrates. This hypothesis would be straightforward to test.

In order to keep my sodium intake sufficiently low during the salt restriction phase, I had to remove shellfish such as oysters and mussels from my diet. Crab is also salty and makes for a handy pun. It seems likely that daily shellfish consumption would have pushed my sodium intake into the healthy range. While shellfish does not get much attention these days in the paleo club, there is ample support (again see Kuipers et. al.) that it was an important contributor to actual paleolithic nutrition.

Hypothesis 2: Humans must drink blood. Or eat salt.

File this one in the “ teen paranormal romance” department. This hypothesis states that the ancestral human diet was not as low in salt as commonly assumed.

Sodium is the body’s primary extracellular cation, and most of it is located in the blood and other extracellular fluids. A pint of blood contains about 1.6 grams of sodium (see, e.g., these livestock reference ranges for blood sodium). That much blood per day should have been more than enough to push me into the healthy range of sodium consumption. On the other hand, salt depletion set in pretty quickly for me (probably 3-4 days), so this hypothesis assumes that fresh blood was consistently available to inland populations that did not have ready access to shellfish or sea water.

I find this hypothesis intriguing because of the fact that my putative ancestors were commanded not to drink blood (Genesis 9:4, Leviticus 17:13, Deuteronomy 12:15-16), and that salt is used in this tradition specifically to remove blood from meat before it is eaten. Presumably blood drinking was outlawed because it was thought to spread diseases and not because of tacky pop-culture connotations. Were my ancestors salting their meat not just for its preservative qualities, but also to make up for the reduction in sodium intake due to their prohibition on drinking blood?

Hypothesis 3: I’m Not (Genetically) a Paleolithic Human

Some say the human genome has hardly changed in the past 10,000 years. However, the hard evidence points to a number of significant evolutionary changes since the advent of agriculture, the classic example being lactase persistance (see Cochran and Harpending 2009 for a thorough argument on the rapidity of recent human evolution). Genes associated with hypertension and salt sensitivity are also apparently under strong evolutionary pressure. Alan Weder discusses this in an article published in 2007 in the journal Hypertension about evolution and hypertension. It is worth reading as an example of excellent science writing.

My experiment clearly demonstrates that I am not salt sensitive. This is not surprising given my European ancestry. As discussed by Weber, the genetics of salt resistance seem to correlate with adaptations to colder climates. It seems possible that in the course of such adaptation, my ancestors lost the ability to function optimally on a low salt diet.

Is a High Salt Diet Safe?

It is possible that, as much of mainstream medicine believes, a high salt diet actually is unhealthy over the long term. There is nothing in this experiment that contradicts that belief. Just because I am resistant to the short term blood pressure effects of salt loading, that does not mean I am immune to whatever long term negative effects a high salt diet may have. While epidemiological studies have their problems, it seems unwise to discount their findings altogether.

Edward Frohlich has argued that, notwithstanding the fact that most people’s blood pressure does not respond to acute increases in sodium intake, sodium is nevertheless responsible long-term for increases in blood pressure. He argues that excess salt causes kidney damage over time (as with uric acid this is mediated by renin/angiotensin systems), resulting long-term in an increase in blood pressure. While much of this research is based on studies done on rats (including those of the “ spontaneously hypertensive” variety), this line of thought is worth looking into and I will continue to do so.