Your Personal Paleo Code: The 3-Step Plan to Lose Weight, Reverse Disease, and Stay Fit and Healthy for Life (13 page)
Authors: Chris Kresser
Tags: #Health & Fitness / Diet & Nutrition / Diets, #Health & Fitness / Diet & Nutrition / Weight Loss
A common misconception is that we can meet our omega-3 needs by taking flax oil or eating plant foods containing ALA. It’s true that the body can convert
some
ALA to EPA and DHA. But that conversion is extremely inefficient in most people. On average, less than 5 percent of ALA gets converted into EPA, and less than 0.5 percent of ALA gets converted into DHA. Since this conversion depends on adequate levels of nutrients such as B
6
, zinc, and iron, these numbers are likely to be even lower in vegetarians, the chronically ill, and the elderly. During the Paleolithic era, consumption of EPA and DHA averaged between 450 and 500 milligrams per day—a figure that greatly exceeds current intakes, which average around 90 to 160 milligrams per day for most Americans. This finding, along with the research indicating extremely poor conversion of ALA to DHA, suggests that we evolved to eat
preformed
EPA and DHA—in other words, readily available EPA and DHA that does not have to be converted from ALA. Research suggests that the ALA-to-EPA/DHA conversion pathway may not have been used at all by our ancestors.
The complete absence of preformed, ready-to-eat DHA in plant foods other than marine algae (which isn’t exactly a staple in Western cuisine) is one of the primary reasons I believe vegetarian and vegan diets are not optimal for health.
One of the most profound differences between traditional, ancestral diets and the modern, industrialized diet is the balance of essential fatty acids consumed. Anthropological research suggests that human intake of omega-6 and omega-3 fats was relatively low throughout most of our history (around 4 percent of total calories), with a ratio of omega-6 to omega-3 of between 1:1 and 2:1.
Today, Americans’ intake of omega-6 fat is far higher than the evolutionary norm, primarily due to increased consumption of industrial seed oils. In addition, we’re eating much less omega-3 than our ancestors used to. Despite a slight increase in fish consumption in recent years (fish being a primary dietary source for omega-3), intake is still far below historical levels. These changes have shifted the range of omega-6-to-omega-3 ratios in the modern diet to between 10:1 and 20:1, with a ratio as high as 30:1 in some individuals! This is between five and thirty times higher than the ratio has been for most of human history. Many scientists believe that this increase in total polyunsaturated fat intake, as well as the dramatic rise in omega-6 consumption relative to omega-3, is at least in part to blame for the rise of chronic conditions like obesity, type 2 diabetes, metabolic syndrome, autoimmune disease, and cardiovascular disease.
A large body of evidence indicates that EPA and DHA are essential to health and that a deficiency of EPA and DHA has played a significant
role in the epidemic of modern inflammatory disease. In general, inadequate intakes of EPA and DHA cause systemic inflammation. Systemic inflammation—the body’s response, through the production of white blood cells and other substances, to infection or other threats—is associated with nearly every modern chronic disease, from arthritis to Alzheimer’s to autoimmune disorders to gastrointestinal diseases. For example:
•
Even modest consumption of EPA and DHA (200 to 500 mg/d) reduces deaths from heart disease by 35 percent—an effect much greater than that observed with statin-drug therapy.
•
DHA is essential for the proper development of the brain and preservation of brain function as we age. Low levels of DHA in pregnant women are associated with lower scores in learning and memory tasks in their offspring, and low DHA levels in the elderly are associated with multiple markers of impaired brain function.
•
Regular consumption of fish or fish oil reduces overall risk of death (that is, total mortality) by 17 percent. Statin drugs reduce total mortality by only 15 percent—and even then, only in populations at very high risk of heart disease.
Mark, age sixty-two, had been an avid golfer his entire life. He played eighteen holes at least three times a week for more than twenty years, and he always walked the course. A few years before he came to see me, however, he began experiencing pain in his shoulders and knees. It got so bad that he had to start using the golf cart, and, more recently, he had stopped playing altogether because he couldn’t swing a club without pain.
I looked at Mark’s diet and noticed that he was eating a lot of omega-6 fat. He ate at restaurants every day during the week (he went out to lunch near his office and got takeout for dinner at least twice a week at home) and often on the weekends too, and his main cooking oil was canola (because he was trying to avoid saturated fat). At the same time, Mark wasn’t eating much omega-3 at all. The only fish he ate was an occasional can of tuna—which is low in EPA and DHA.
I asked Mark to start bringing a lunch to work and to cut back on takeout at home. Restaurant kitchens use primarily industrial seed oils rich in omega-6 linoleic acid to prepare their food, because these oils are so cheap. I also alleviated his fears about saturated fat and instructed him to cook with ghee, coconut oil, butter, tallow, and lard instead of canola oil. Finally, I told Mark to eat at least four five-ounce servings of cold-water, fatty fish, like salmon, mackerel, herring, or sardines, every week.
After six weeks on this program, Mark came back to the office beaming. He was able to walk without pain for the first time in three years, and he was back out on the golf course—on foot, instead of in the cart. Don’t underestimate the power of simple dietary changes!
There are two ways to increase your levels of EPA and DHA:
•
Significantly reduce the amount of LA you consume.
•
Eat sufficient amounts of preformed EPA and DHA.
Both of these steps are important. As you’ve read, even when intake of LA is low, the conversion of ALA to EPA and DHA is negligable. And eating too much LA—even with adequate EPA and DHA intake—can be harmful. As I explained in
chapter 4
, excess LA has been shown to cause vitamin E depletion, intestinal dysbiosis, oxidative damage, and inflammation as well as contribute to weight gain, liver disease, cancer, autoimmune disease, inflammatory bowel disease, and premature aging.
•
Omega-3 ALA:
Found in fruits, vegetables, nuts and seeds, especially walnuts and flax
•
Omega-3 EPA and DHA:
EPA and DHA are found primarily in cold-water, fatty fish, like salmon, mackerel, herring, sardines, anchovies, and bass, as well as in shellfish, like oysters and mussels, and, to a much lesser extent, in meat from grass-fed animals and from wild game. It’s important to note that freshwater fish, many species of ocean fish, and farmed fish are generally lower in EPA and DHA and therefore not as beneficial.
Food
: Caviar (fish eggs)
EPA + DHA Per 3 Oz.
: 5.5 g
Food
: Herring
EPA + DHA Per 3 Oz.
: 1.8 g
Food
: Salmon, farmed
EPA + DHA Per 3 Oz.
: 1.8 g
Food
: Anchovy
EPA + DHA Per 3 Oz.
: 1.7 g
Food
: Mackerel
EPA + DHA Per 3 Oz.
: 1.5 g
Food
: Salmon, wild
EPA + DHA Per 3 Oz.
: 1.5 g
Food
: Bluefin tuna
EPA + DHA Per 3 Oz.
: 1.3 g
Food
: Oyster
EPA + DHA Per 3 Oz.
: 1.1 g
•
Omega-3 alpha-linoleic acid (ALA): Consume in moderation
in whole foods like fruits, vegetables, and seeds. Avoid large amounts of flax oil and flax seed, which unnecessarily increase total polyunsaturated fat intake without significantly increasing EPA and DHA.
•
Omega-3 EPA and DHA: Eat liberally.
How much fish should you eat to get the benefits of EPA and DHA? According to some studies, death from heart disease can be reduced by 25 percent or more if you consume about 3.5 grams of EPA plus DHA per week. This is equivalent to about ten ounces a week of wild salmon. However, studies of Western populations without substantial amounts of EPA and DHA in their diets (and with higher amounts of LA in their diet) suggest a continued reduction of cardiovascular disease when an individual consumes up to seven grams of EPA and DHA per week, which is about twenty ounces of wild salmon. With this in mind, I recommend the following:
If you’re healthy and free of heart disease and your intake of LA is relatively low, aim for the lower-end target of 3.5 grams of EPA/DHA, or ten ounces of fish a week.
If you’re at risk for heart disease or you’re unable to significantly reduce your intake of LA (perhaps you eat out a lot), aim for the upper end of the range at 7 grams of EPA/DHA or twenty ounces per week.
Be aware that, depending on the dose of EPA and DHA, it takes about three to six months to reestablish a healthy balance of long-chain omega-3 polyunsaturated fats in the tissues.
Why not just take twenty grams of fish oil per day to change your tissue levels of EPA and DHA as quickly as possible? The answer is that all polyunsaturated fats are highly vulnerable to oxidative damage—a process associated with cancer, heart disease, and other inflammatory conditions—and EPA and DHA are no exception. In fact, they are the most vulnerable of all fats. A randomized trial showed that six grams per day of fish oil increased oxidative damage in healthy men regardless of whether their diets were supplemented with 900 IU of vitamin E (an antioxidant).
This argues for getting the majority of EPA and DHA from cold-water, fatty fish in the diet rather than from fish oil. Supplementing with fish oil should be reserved for therapeutic purposes and should usually be short-term and limited to two to three grams per day, depending upon
background fish intake. The exception would be cod-liver oil, which tends to have relatively low levels of EPA and DHA compared to other fish oils but is rich in important fat-soluble vitamins like A and D. (I’ll discuss cod-liver oil and therapeutic supplementation with fish oil in later chapters.)
Saturated fats and monounsaturated fats should form the bulk of your fat intake. The omega-3 fats EPA and DHA and the omega-6 fat arachidonic acid should be consumed regularly, while omega-6 linoleic acid should be consumed only in whole-food form (nuts, seeds, avocados) in moderate amounts. See my website for a printable version of this list as a chart that you can put on your fridge.
Eat Liberally
Coconut oil
Palm oil
Olive oil
Ghee
Butter
Lard
*
Tallow (beef and lamb)
Duck fat
*
Dairy fat
Macadamia oil
Eggs, meat, and seafood
Eat in Moderation
Sesame oil
Walnut oil
Pecan oil
Almond oil
Flaxseed oil
Avocado oil
Nuts and seeds
Nut butters
Avoid
Soybean oil
Peanut oil
Corn oil
Safflower oil
Wheat-germ oil
Canola oil
Sunflower oil
Cottonseed oil
Grape-seed oil
Rice bran oil
When choosing fats for cooking, it’s important to be aware of their smoke point. The smoke point is the temperature at which the flavor and nutritional integrity of the fat or oil begin to break down. Once an oil exceeds its smoke point, it will usually produce a bluish and pungent smoke that is irritating to the eyes. Oils that have passed their smoke point are likely to contain oxidized fats, which have been shown to damage cells and contribute to numerous diseases.