the-psoriasis-treatment

Natural selection granted us large brains. The evolutionary cost is having to feed them. The human brain's high-energy demands led to development of a strong preference for fat. We consume more fat than any other primate on average. We are also adapted to more easily digest and metabolize fats. There are two major kinds of fat that our brains depend on most for its development and regular maintenance. These are the long-chain polyunsaturated fatty acids (LC-PUFAs), omega-3 docosahexaenoic acid (DHA) and omega-6 arachidonic (AA). These two LC-PUFAs can't be made de novo , making them essential in the diet. DHA and AA are supplied by seafood, eggs, or animals. They can also be supplied as their 18-carbon precursors alpha-linolenic acid (ALA) and linoleic acid (LA), found mainly in plants and their seeds. ALA and LA precursors require conversion to become long-chained through a series of steps of desaturation and elongation. In particular, delta-5 and delta-6 fatty acid desaturase...

Anyone who is keenly interested in having a better understanding of why we eat what we eat as human beings should take an hour or so to watch this introductory talk given by anthropologist Teresa Steele , of UC Davis, given at the California Academy of Sciences on the topic of evolution of the human diet. I found her talk fascinating, especially because I've been highly interested in how the use of fire and aquatic animals may have played a part in fueling human brain growth, so I ended up taking copious notes. I should note that there isn't anything new presented here, but Steele is excellent at presenting the chronology. If you don't have an hour to watch, then just see my notes below chapter by chapter from " Australopithecus to agriculture." Human diet is unique among apes Steele finds that diet is central to her research. "If we want to live, we have to eat," she says. Food is what ultimately supports demographic populations. One thing that is uniq...

The bar chart below shows the fat content of 1 sardine (38 g) canned in tomato sauce, and 2 fish oil softgels of the Nature Made brand. (The sardine is about 1/3 of the content of a typical can, and the data is from Nutritiondata.com. The two softgels are listed as the “serving size” on the Nature Made bottle.) Both the sardine and softgels have some vegetable oil added; presumably to increase their vitamin E content and form a more stable oil mix. This chart is a good reminder that looking at actual numbers can be quite instructive sometimes. Even though the chart focuses on fat content, it is worth noting that the 38 g sardine also contains 8 g of high quality protein. If your goal with the fish oil is to “neutralize” the omega-6 fat content of your diet, which is most people’s main goal, you should consider this. A rough measure of the omega-6 neutralization “power” of a food portion is, by definition, its omega-3 minus omega-6 content. For the 1 canned sardine, this difference is 5...

Nuts are generally seen as good sources of protein and magnesium. The latter plays a number of roles in the human body, and is considered critical for bone health. Nuts are also believed to be good sources of vitamin E. While there is a lot of debate about vitamin E’s role in health, it is considered by many to be a powerful antioxidant. Other than in nuts, vitamin E is not easily found in foods other than seeds and seed oils. Some of the foods that we call nuts are actually seeds; others are legumes. For simplification, in this post I am calling nuts those foods that are generally protected by shells (some harder than others). This protective layer is what makes most people call them nuts. Let us see how different nuts stack up against each other in terms of key nutrients. The quantities listed below are per 1 oz (28 g), and are based on data from Nutritiondata.com. All are raw. Roasting tends to reduce the vitamin content of nuts, often by half, and has little effect on the mineral c...

A while back I wrote a review of Queen of Fats: Why Omega-3s Were Removed from the Western Diet and What We Can Do about Them . Susan Allport's book goes into the history of how omega-3s were discovered and what they'll mean for us in the future. A controversial topic of the book is how omega-6 (king) and omega-3 (queen) compete for space in eicosanoid pathways. The omega-6s, the king, are the greater competitor and more inflammatory, while the omega-3, the queen, are a lesser competitor and less inflammatory. She goes on about this relationship between omega-6 and omega-3 and gives examples from nature of how both the oils are found and used -- omega-3s in leaves (leaf fats), omega-6s in seeds (seed fats); omega-3s eaten more often in summer months, omega-6s in winter months by animals. The omega-6s are thought to bring on extra fat for warmth, for storage, for hibernation. It's all pretty interesting stuff. And again, as I said, a bit controversial. Now, in a new article...

Just a little note on the use of language. Clearly there is no such a thing as grain-fed or grass-fed beef, because one does not feed beef anything. One feeds cattle grain or grass, and then the resulting beef is said to be “grain-fed” or “grass-fed”. It is a manner of speaking that facilitates discourse, which is why it is used here. To compensate for this digression, let me show you a graph, which pretty much summarizes the "punch line" of this post. The graph below shows the omega-6 fat contents of 1 lb (454 g) of grain-fed beef and 1 tablespoon (roughly 14 g) of a typical industrial vegetable oil (safflower oil). As you can see, there is a lot more omega-6 in the much smaller amount of industrial vegetable oil. A gram-for-gram comparison would practically make the beef content bar disappear. It has been estimated that our Paleolithic ancestors consumed a diet with an omega-6 to omega-3 ratio of about 1 . While other estimates exist, the general consensus seems to be that ...

This is a follow up on this post , which addressed the main argument put forth in a recent BBC article. The BBC article argued that people should replace saturated with polyunsaturated fats to reduce their risk of heart disease. Let us take a look at the actual Harvard study itself (i.e., the study discussed in the BBC article). The Harvard study is linked here . This post , by Stephan Guyenet, already pointed out several problems with the study. Stephan actually reviewed the studies used in the meta-analysis, and also some that were excluded in the meta-analysis and that he believes should have been included. Here are a few other problems, in addition to the ones already pointed out by Stephan: One thing that looks suspicious about this Harvard meta-analysis study is that they say that: “Statistical evidence for substantial between-study heterogeneity was not present (Q-statistic p = 0.13; I2 = 37%).” A meta-analysis is a study that essentially summarizes, in a statistically sophistic...

The BBC article is here . It is based on meta-analysis of eight previous studies conducted by Harvard researchers, which the article states cover more than 13,000 people. The article also says that: “… [saturated] fats raise the levels of bad cholesterol that block the arteries to the heart.” They are of course referring to LDL cholesterol as the "bad cholesterol". Sourcing bias is a notorious problem with meta-analyses (i.e., the choice of studies to use in a meta-analysis). Another problem is that you cannot tell what the studies sourced controlled for. Consider a study that compares health markers for smokers and non-smokers, where the smokers eat more saturated fat than the non-smokers. This study may confuse the effect of smoking with that of saturated fat consumption. To be reliable, the study must analyze the effect of saturated fat consumption, controlling for smoking habits. There are other statistical issues to be considered in meta-analyses. For example, some of th...

Few would argue against eating seafood several times a week, except in the case of seafood allergy. Shrimp is a very good option, especially if it is not farm raised. 100 g of shrimp will typically have 20 g of protein, and about 152 mg of cholesterol (this is good for your health ). It will also have about 0.6 g of omega-3 fats, and 0.03 g of omega-6; an omega-3 to omega-6 ratio of about 20. My wife prepared this steamed gulf shrimp with vegetables dish. And it was very, very delicious. Here is her recipe: - Add a small amount of olive oil and water to a frying pan. - Add 1 lb of wild-caught peeled gulf shrimp, cabbage, onion, and asparagus (or green beans, as in the photo). - Cook in low heat for 15 minutes. - Add spinach and cook in low heat for another 10 minutes. - Turn off heat, season to taste while mixing; I suggest using garlic powder, cumin powder, and parsley flakes. Peeled shrimp is usually farm raised, which does not have the same amount of omega-3, or the same ratio of om...

Different parts of a fish have different types of nutrients that are important for our health; this includes bones and organs. Therefore it makes sense to consume the fish whole, not just filets made from it. This is easier to do with small than big fish. Small fish have the added advantage that they have very low concentrations of metals, compared to large fish. The reason for this is that small fish are usually low in the food chain, typically feeding mostly on plankton, especially algae. Large carnivorous fish tend to accumulate metals in their body, and their consumption over time may lead to the accumulation of toxic levels of metals in our bodies. One of my favorite types of small fish is the sardine. The photo below is of a dish of sardines and vegetables that I prepared recently. Another small fish favorite is the smelt (see this post ). I buy wild-caught sardines regularly at the supermarket. Sardines are very affordable, and typically available throughout the year. In fact, s...

As I blog about health issues, and talk with people about them, I often notice that there is a growing contempt for the medical profession. This comes in part from the fact that many MDs are still providing advice based on the mainstream assumption that saturated fat is the enemy. Much recent (and even some old) research suggests that among the main real enemies of good health are: chronic stress, refined carbs, refined sugars, industrial trans-fats, and an omega-6/omega-3 imbalance caused by consumption of industrial vegetable oils rich in omega-6 fats. Because of this disconnect, some people stop seeing their doctors regularly; others avoid doctors completely. Many rely exclusively on Internet advice, from health-related blogs (like this) and other sources. In my opinion, this is a BIG mistake. A good MD has something that no blogger who is not an MD (like me) can have. He or she has direct access to a much larger group of people, and to confidential information that can clarify thin...

I would like to comment on a recent article co-authored by Dr. Loren Cordain, and published in the journal Current Treatment Options in Cardiovascular Medicine, in 2009. Dr. Cordain is probably the leading expert today on the diet of our Stone Age ancestors. The importance of this article comes from the fact that in the past Dr. Cordain has argued that our Stone Age ancestors have not consumed large amounts of saturated fat, because of the relatively low percentage of fat in the flesh of wild animals. This led, according to Dr. Cordain, to an evolved body design that is not well adapted to the consumption of significant amounts of saturated fat. Yet, many other researchers have argued that saturated fats are beneficial to our health, with ample empirical evidence to back up their statements. The researchers at the Weston A. Price Foundation have been particularly prominent voices in favor of saturate fats. Now, this acknowledgement that saturated fats (or saturated fatty acids) are n...

Purpose of study: Observe how plasma n-3 fatty acids affect risk of cognitive decline in older adults. Research methodology: Prospective human observational cohort study Description: Beydoun et al (1) analyzed plasma fatty acids in cholesteryl esters and phospholipids in 2,251 white women and men ages 50-65 from 1987 to 1989 in a community in Minneapolis, MN. In subsequent years 1990 to 1992 and 1996 to 1998, researchers administered cognitive tests on the subjects. Measurements: Blood analysis was performed through collection of 12-hour fasting blood followed by identity of peaks through gas chromatography. Reliability coefficient for the testing ranged from 0.50 to 0.93 for cholesteryl esters and from 0.50 to 0.89 for phospholipids. Cognitive assessments included tests for delayed word recall, psychomotor speed and verbal fluency. The researchers properly noted that almost all subjects had education of high school or above, which was important to assure group comparability. Ages 6...