Life, the Universe, and Everything

More Ancestral Diet Evidence

Posted by Peter on June 24, 2013
Posted in: Health. Tagged: , .

There was a large shift in our ancestors diet about 3.5 million years ago to food derived from grasses and/or sedges. This has potentially important implications for what diet we’re adapted to. Unfortunately, the evidence isn’t specific enough to be very useful:

The isotope method cannot distinguish what parts of grasses and sedges human ancestors ate – leaves, stems, seeds and-or underground storage organs such as roots or rhizomes. The method also can’t determine when human ancestors began getting much of their grass by eating grass-eating insects or meat from grazing animals.

Paleofantasy

Posted by Peter on April 26, 2013
Posted in: Book Reviews, Health. Tagged: , , .

Book review: Paleofantasy: What Evolution Really Tells Us about Sex, Diet, and How We Live, by Marlene Zuk

This book refutes some myths about what would happen if we adopted the lifestyle of some imaginary hunter-gather ancestor who some imagine was perfectly adapted to his environment.

I’m a bit disappointed that it isn’t as provocative as the hype around it suggested. It mostly just points out that there’s no single environment that we’re adapted to, plus uncertainty about what our ancestors’ lifestyle was.

She spends a good deal of the book demonstrating what ought to be the well-known fact that we’re still evolving and have partly adapted to an agricultural lifestyle. A more surprising point is that we still have problems stemming from not yet having fully evolved to be land animals rather than fish (e.g. hiccups).

She provides a reference to a study disputing the widely held belief that the transition from hunter-gatherer to farmer made people less healthy.

She cites evidence that humans haven’t evolved much adaptation to specific diets, and do about equally well on a wide variety of diets involving wild foods, so that looking at plant to animal ratios in hunter-gather diets isn’t useful.

Her practical lifestyle advice is mostly consistent with an informed guess about how we can imitate our ancestors’ lifestyle (e.g. eat less processed food), and mainly serves to counteract some of the overconfident claims of the less thoughtful paleo lifestyle promoters.

Anti-Paleo Diet

Posted by Peter on March 3, 2013
Posted in: Health. Tagged: .

Soylent is an almost pure chemical diet, whose most natural looking ingredients are olive oil and whey protein. It provides the FDA recommended nutrients from mostly purified sources of the individual nutrients. The creator claims to have experienced improved health after adopting it (after previously eating something slightly better than a typical US diet).

This seems like a very effective way to minimize the poisons in our diet.

It’s also cheaper than most diets (he claims less than $2/day, but that seems questionable). He claims it tastes good, although eating the same thing day after day would seem a bit monotonous.

FDA recommendations are known to be suboptimal – too little vitamin D, too much calcium.

He seems confused about the fiber requirements, and is a bit reckless about his omega-6/omega-3 ratio. But these are easily improved.

He almost certainly misses some important nutrients that haven’t yet been identified, but that can be partly compensated for by adding a few low-risk foods such as salmon, seaweed, spinach, and sweet potatoes (the four S’s?).

I’m giving some thought to replacing 25-50% of my calories with something along these lines.

Talking20

Posted by Peter on January 10, 2013
Posted in: Health.

Talking20 is an ambitious startup attempting to make a wide variety of blood tests available at the surprisingly cheap price of $2 per test. Getting the drop of blood needed will still be a pain, but doing it at home and mailing in a postcard will simplify the process a lot.

If this succeeds it would dramatically increase our knowledge of things such as our cholesterol levels.

But I get the impression that they are being rather optimistic about how quickly they can get enough sales volume to make money.

Their attempt to use Indiegogo doesn’t appear to be as appropriate to their needs as seeking angel or VC investment would be.

I’m also concerned that the institutions they would compete with will try to get them regulated in ways that would drastically increase their costs.

I’m somewhat tempted to order something from them via Indiegogo, but I’m not confident in their ability to deliver.

How to Measure Anything

Posted by Peter on December 28, 2012
Posted in: Book Reviews, Life, the Universe, and Everything. Tagged: , .

Book review: How to Measure Anything, by Douglas Hubbard.

I procrastinated about reading this book because it appeared to be only relevant to a narrow type of business problem. But it is much more ambitious, and aims to convince us that anything that matters can be measured. It should be a good antidote to people who give up on measuring important values on grounds such as it’s too hard or too subjective (i.e. it teaches people to do Fermi estimates).

A key part of this is to use a sensible definition of the word measurement:

A quantitatively expressed reduction of uncertainty based on one or more observations

.

He urges us to focus on figuring out what observations are most valuable, because there are large variations in the value of different pieces of information. If we focus on valuable observations, the first few observations are much more valuable than subsequent ones.

He emphasizes the importance of calibration training which, in addition to combating overconfidence, makes it hard for people to claim they don’t know how to assign numbers to possible observations.

He succeeds in convincing me that anything that matters to a business can be measured. There are a few goals for which his approach doesn’t seem useful (e.g. going to heaven), but they’re rarer than our intuition tells us. Even vague-sounding concepts such as customer satisfaction can either be observed (possible with large errors) via customer behavior or surveys, or they don’t matter.

It will help me avoid the temptation of making Quantified-Self types measurements to show off how good I am at quantifying things, and focus instead on being proud to get valuable information out of a minimal number of observations.

Food and Western Disease

Posted by Peter on December 4, 2012
Posted in: Book Reviews, Health. Tagged: , , .

Book review: Food and Western Disease: Health and nutrition from an evolutionary perspective, by Staffan Lindeberg.

This book provides evidence that many causes of death in developed nations are due to a lifestyle that is different from hunter-gatherer lifestyles.

His studies of existing hunter-gatherer societies show moderately good evidence that cardiovascular disease is rare, that aging doesn’t cause significant dementia, and shows weaker evidence of less cancer.

He has some vaguely plausible reasons for focusing on diet as the main lifestyle difference. I’m disappointed that he doesn’t mention intermittent fasting as a factor worth investigating (is it obvious from his experience that some hunter-gatherer societies don’t do this?).

He uses this evidence to advocate a mostly paleo diet, although with less fat than is often associated with that label.

Much of the book is devoted to surveying the evidence about other proposed dietary improvements, mostly concluding they don’t do much (or in the case of calorie restriction, might work by causing a more paleo-like diet).

I don’t have a lot of confidence in his ability to interpret the evidence.

He gives the impression that Omega-3 consumption has little effect on health, citing papers such as this review, whose abstract includes:

showed no strong evidence of reduced risk of total mortality (relative risk 0.87, 95% confidence interval 0.73 to 1.03)

I’d call that evidence for a moderately important benefit of Omega-3, and I consider it strong evidence in comparison to typical dietary studies, although it’s weak compared to the evidence that other scientific fields aim for.

One response from nutrition experts says:

The null conclusion of the Cochrane report rests entirely upon inclusion of one trial, DART 2.

A quick glance at recent publications from another author he cites (Mozaffarian) got me this:

Considerable research supports cardiovascular benefits of consuming omega-3 PUFA, also known as (n-3) PUFA, from fish or fish oil.

Excessive skepticism is probably better than hype, but it will discourage many people from reading it. Plus the style is somewhere in between a reference book and a book that I’d read from start to end.

Quantified Self Conference

Posted by Peter on October 10, 2012
Posted in: Health, Science and Technology. Tagged: , , .

The recent Quantified Self conference was my first QS event, and was one of the best conferences I’ve attended.

I had been hesitant to attend QS events because they seem to attract large crowds, where I usually find it harder to be social. But this conference was arranged so that there was no real center where crowds gathered, so people spread out into smaller groups where I found it easier to join a conversation.

Kevin Kelly called this “The Measured Century”. People still underestimate how much improved measurement contributed to the industrial revolution. If we’re seeing a much larger improvement in measurement, people will likely underestimate the importance of that for quite a while.

The conference had many more ideas than I had time to hear, and I still need to evaluate many of he ideas I did hear. Here are a few:

I finally got around to looking at DIYgenomics, and have signed up for their empathy study (not too impressive so far) and their microbiome study (probiotics) which is waiting for more people before starting.

LUMOback looks like it will be an easy way to improve my posture. The initial version will require a device I don’t have, but it sounds like they’ll have an Android version sometime next year.

Steve Fowkes’ talk about urine pH testing sounds worth trying out.

Cholesterol, Saturated Fat and ApoE4

Posted by Peter on September 22, 2012
Posted in: Health. Tagged: , .

This past spring I adopted a diet resembling Dave Asprey’s. After about 5 weeks on it, I took a fancy blood test (trying to optimize things such as my vitamin D levels, Omega-6/Omega-3 ratio, etc). When I finally got the results back, I was shocked to find that the most important results involved my cholesterol levels.

Six years earlier my cholesterol had been good enough that I hadn’t had any reason to pay attention to it. But this May it was 369, with an LDL of 208, and an amazingly good HDL of 108.

If I’d been unlucky enough to get those results from Kaiser, I’d have felt helpless for quite a while. But the WellnessFX report also mentioned that my ApoE Genotype is 3/4. When I got around to researching the implications of that, I figured out that the ApoE4 gene can contribute to some unusual reactions to fat, and that a few people with a copy of it had reported skyrocketing cholesterol in response to a diet of paleo foods plus much coconut and grass-fed butter.

So I cut back on my fat intake, and figured out how to test how my diet affects my cholesterol. I’ve been using CardioChek about once a week. It’s unreliable (about 50 mg/dL too low, judging by my two comparisons with Kaiser). And I’ve only been getting total cholesterol numbers. I could get better info by also measuring HDL with it and subtracting that from the total to get the number that I really want to reduce. But that would require getting a second blood sample, and I barely have enough patience to take one good sample (I often end up with too little blood and need to start over).

With all the uncertainty about the accuracy of those numbers and the time delay between altering my fat intake and when my cholesterol levels showed my response, I wasn’t too optimistic about getting clear results. But the first ways I quantified the evidence gave correlations of 0.540 or 0.418 using 12 or 13 data points (the first of those excludes an implausibly low reading the first time I used it). That’s using an exponential moving average of my saturated fat intake that roughly corresponds to the past week. Other averages of my saturated fat intake have produced somewhat similar results.

My saturated fat consumption ranged 23.5 to 53 grams per day for that data, and the cholesterol levels at the high end of the range are something like 30-50 mg/dL higher than the low end.

So I see a clear and moderately strong connection.

My limited attempts to analyze subclasses of saturated fat have been inconclusive.

Now, how good or bad is the combination of very healthy HDL and disturbingly high LDL?

There are a variety of algorithms to estimate my risk based on my cholesterol levels. Some weight LDL heavily and say I ought to be concerned about the higher readings. Others weight HDL more, and say I’m unusually healthy. The TC/HDL criterion says I have improved with each of the tests I’ve taken [excluding the home tests that only measured TC].

Without strong evidence about which algorithm is more reliable, I’m disposed to keep my cholesterol somewhat close to normal levels.

What about the evidence that societies with high coconut consumption are healthy? That could mean that high cholesterol with ApoE4 is a healthy sign – the body sees lots of rich food, and decides it devote more resources than normal to reducing inflammation. Or it might mean that ApoE4 genes got selected out of those populations.

It looks like coconuts have been eaten for the longest time in islands of the west Pacific, with the Philippines currently having the highest consumption for a sizable country, and high consumption extending west to India.

According to this study the ApoE4 prevalence in countries from the Philippines to India (including China, which presumably hasn’t had much dietary coconut in the north) ranges from 6 to 10 percent, as opposed to 17 percent in the US (which is about average). (This paper(paywalled) has some different-looking numbers on a not very readable map.)

So it looks like there has been enough selection against ApoE4 in those areas that I shouldn’t feel safe eating lots of coconut fat. But I suspect that there are other relevant genes which make it hard to generalize to everyone with an ApoE4 gene.

Eating Insects

Posted by Peter on September 5, 2012
Posted in: Health. Tagged: .

In my quest for a diet that more closely resembles what we evolved to eat, I tried eating some insects.

Fluker’s Gourmet Canned Mealworms are ok, but the taste isn’t memorable. The texture is interesting, but hardly a reason to eat them again. They’re sold as pet food, and labeled not for human consumption. That might mean too much bacteria, but cooking should kill those. Could they have pesticides? Maybe, but insects are usually what pesticides kill, so it would be odd to use pesticides to grow them.

I tried some insects from Hotflix, which markets them as candy. All seem to be coated with varying amounts of sugar. The “chocolate covered insects” are mostly packaging, and have an ingredient list that includes hydrogenated oil but no chocolate. The various flavors of Larvets are better – mostly insect with only a small amount of sugar, spices, and artificial flavor or color. The spices make them taste fairly good, but the price per gram makes them too expensive to be a reasonable source of significant nutrition, and the artificial additives make me consider them less safe to eat than the bugs sold as pet food.

It seems like there ought to be a way to get affordable healthy nutrition from insects, and I’ll keep looking occasionally, but we probably need more demand for economies of scale to make that practical.

Omega-6 Revisited

Posted by Peter on August 18, 2012
Posted in: Health. Tagged: .

I’ve researched omega-6 some more and the evidence that it is harmful is much less clear than I previously thought.

There’s some evidence that omega-6/omega-3 ratios above some threshold (between 2.5 and 4?) are harmful, but also arguments against focusing on the ratio:

This paper reviews a variety of studies that, in the aggregate, suggest that the ratio is, both on theoretical and evidential grounds, of little value. Metrics that include the n-3 FAs alone, especially eicosapentaenoic and docosahexaenoic acids, appear to hold the greatest promise.

While omega-6 can be converted into proinflammatory molecules, it also has antiinflammatory properties.

in observational studies, higher omega-6 PUFA consumption was associated with unaltered or lower levels of inflammatory markers

in 1 study in Israel,39 where 25% of the population consumes >12% of energy as omega-6 PUFA, an inverse association was found between adipose LA [Linoleic acid] and acute myocardial infarction after controlling for other omega-6 PUFAs.

This meta-analysis seems to be the most rigorous analysis:

They looked for

all RCT that increased PUFA and reported relevant CHD outcomes

For non-fatal myocardial infarction (MI)+CHD death, the pooled risk reduction for mixed n-3/n-6 PUFA diets was 22 % (risk ratio (RR) 0·78; 95 % CI 0·65, 0·93) compared to an increased risk of 13 % for n-6 specific PUFA diets (RR 1·13; 95 % CI 0·84, 1·53).

They found 7 randomized trials that raised omega-6 levels and provided a tolerable amount of info about other fats. Three that had apparently low dietary omega-3 showed that higher omega-6 combined with lower trans-fats produced more heart disease/death (i.e. above some high omega-6/omega-3 ratio, omega-6 can cause more harm than trans-fats), while four where the higher omega-6 was combined with arguably adequate omega-3 and lower trans-fats had less heart disease/death with that combination (i.e. omega-6 might have helped or might have caused harm that was small compared to trans-fats).

From another paper:

High intakes of linoleic acid were not associated with excess risk of AMI [acute myocardial infarction]
…
arachidonic acid, the long chain n?6 derivative of linoleic acid, was positively associated with AMI

(Arachidonic acid is found mainly in eggs, meat, and seafood).

Other sources suggest arachidonic acid is safe, mentioning studies of biomarkers that show no harm from arachidonic acid, but biomarkers are less convincing than actual disease. There are some reports that ratio of arachidonic acid to eicosapentaenoic acid (AA:EPA) in blood plasma is a useful measure of cardiovascular problems.

In my previous post I expressed doubts about high omega-3 diets, but this paper on hunter-gatherer diets gives the following estimates for fat intake:

  • Omega-3 9.6g/day
  • Omega-6 14.2g/day
  • Saturated 18g/day
  • Monunsaturated 44.3g/day

I don’t know how typical this is of our ancestors, but at least it’s likely within the range of diets that we’re adapted to. This suggests it’s hard to get too much omega-3 or too much fat from seafood (I’d get too much protein if I ate much more than 2 pounds of salmon, but not too much of any type of fat). It also suggests that it’s reasonable to aim for high enough omega-3 that I can’t easily get an omega-6/omega-3 ratio that is high enough to be of much concern.

More from that paper:

Compiled ethnographic studies of 229 hunter-gatherer societies, as well as quantitative studies of hunter-gatherers have demonstrated that animal foods contributed slightly more than half (55-65%) of the daily energy, whereas plant foods would have made up the remainder (35-45%) of the average daily caloric intake. Of the energy obtained from animal foods, historically-studied hunter-gatherers typically derived half of their energy from aquatic animals and the other half from terrestrial animals. Animal food intake would have also been constrained by the physiologic protein ceiling, which has been shown to occur between 30 to 41% of total energy.

There is an increasing body of evidence that suggests high protein diets may improve blood lipid profiles and thereby lessen the risk for cardiovascular disease (CVD).

[I plan to check this evidence later.]