The Paleo Diet for Athletes (33 page)

MUFA=monounsaturated fatty acids; PUFA = polyunsaturated fatty acids; SAT = saturated fatty acids

What’s Wrong with Peanut Oil and Peanuts?

If you look at peanut oil fatty acid composition in
Table 11.4
, you’ll see that almost 80 percent is made up of cholesterol-lowering monounsaturated and polyunsaturated fats. Hence, on the surface, you might think that peanut oil would be helpful in preventing the artery-clogging process (atherosclerosis) that underlies coronary heart disease. Well, your idea is not a whole lot different from what nutritional scientists believed—that is, until they got around to actually testing peanut oil in laboratory animals. Starting in the 1960s and continuing into the 1980s, scientists found peanut oil to be unexpectedly atherogenic, causing arterial plaques to form in rabbits, rats, and primates—only a single study showed otherwise. In fact, peanut oil is so atherogenic that it continues to be routinely fed to rabbits to stimulate atherosclerosis to study the disease itself.

At first, it was not clear how a seemingly healthful oil could be so toxic in such a wide variety of animals. Then, in a series of experiments, David Kritchevsky, PhD, and colleagues at the Wistar Institute
in Philadelphia showed that peanut oil lectin (PNA) was most likely responsible for the artery-clogging properties. A lectin is a fairly large protein molecule, and most nutritional scientists had assumed that digestive enzymes in the gut would degrade it into its component amino acids, so the intact lectin molecule would not be able to get into the bloodstream to do its dirty work. But they were wrong. It turned out that lectins were highly resistant to the gut’s protein-shearing enzymes. An experiment conducted by Dr. Wang and colleagues and published in the prestigious medical journal
Lancet
revealed that PNA gets into the bloodstream intact in as little as 1 to 4 hours after participants ate a handful of roasted, salted peanuts. Even though the concentrations of PNA in the blood were quite low, they were still at amounts known to cause atherosclerosis in animal experiments. Lectins are a lot like super-glue—it doesn’t take much. Because these proteins contain carbohydrates, they can bind to a wide variety of cells in the body, including the cells lining the arteries. And indeed, it was found that PNA did its damage to the arteries by binding to a specific sugar receptor. So, the practical point here is to stay away from both peanuts and peanut oil. There are better choices.

How about Canola Oil?

Since the publication of
The Paleo Diet for Athletes
in 2005, I have now reversed my position on canola oil and can no longer support its consumption or use. Let me explain why. Cano la oil is extracted from the seeds of the rape plant (
Brassica rapa
or
Brassica campestris
), which is a member of the broccoli, cabbage, Brussels sprouts, and kale family. Unquestionably, humans have eaten cabbage and its botanical relatives before historical times, and I still solidly support consumption of these healthy veggies. However, the concentrated oil from
Brassica
seeds is an entirely different proposition.

Before genetic modification by agronomists, rape plants produced a seed oil that maintained high levels (20-50 percent) of erucic acid (a monounsaturated fatty acid; lipid name: 22:1v9), which is toxic and
causes tissue injury in many organs of experimental animals. In the 1970s, Canadian plant scientists developed a strain of rape plant that produced a seed with less than 2 percent erucic acid (hence the name canola oil). The erucic acid concentration of store-bought canola oil averages 0.6 percent. Nevertheless, several experiments in the 1970s demonstrated that even at low concentrations (2.0 percent and 0.88 percent), canola oil fed to rats could still cause small heart scarring that was deemed “pathological.” A succession of current rat studies of low erucic canola oil performed by Dr. Naoki Ohara and colleagues at the Hatano Research Institute in Japan reported kidney injuries, elevations in blood sodium concentrations, and irregular alterations to a hormone (aldosterone) that controls blood pressure. Other adverse effects of canola oil consumption in animals at 10 percent of calories include decreased litter sizes, behavioral changes, and liver damage. A number of current human studies of canola/rapeseed oil by Sanna Poikonen, MD, and coworkers at the University of Tampere in Finland indicated it to be a potent allergen in adults and children that causes allergic cross-reactions from other environmental allergens. Based upon these brand-new findings in both humans and animals, I favor to err on the safe side, and can no longer recommend canola oil as a part of contemporary Paleo diets.

Nuts and Seeds

Except for peanuts, we recommend all nuts and seeds as healthful components of the Paleo Diet for Athletes. Many people have food allergies, and nuts are one of the more common ones. Always listen to your body; if you know or suspect that nuts do not agree with you, then don’t eat them. This advice holds for all foods, including shellfish, which also frequently causes allergies. In
Table 11.5
, you can see the fatty acid balance for commonly available nuts. Notice that except for walnuts and macadamia nuts, all other nuts maintain high ratios of omega-6 to omega-3. The ideal ratio in your diet should be about 2:1 or slightly lower. Because nuts are so calorically dense, they can very easily derail the best-laid dietary plans. If you use nuts as staples—rather than lean meats, seafood, and fresh fruits and veggies—chances are that you will not get sufficient omega-3 fatty acids in your diet. Enjoy nuts, but use them carefully.

Table 11. 5

Fatty Acid Composition of Nuts and Seeds

MUFA = monounsaturated fatty acids; PUFA = polyunsaturated fatty acids; SAT = saturated fatty acids

CHEATING

The Paleo Diet for Athletes is actually not a diet at all but, rather, a lifelong pattern of eating that, besides improving athletic performance, will
normalize body weight and reduce the risk for heart disease, cancer, and osteoporosis. It also plays a significant role in treating diabetes, hypertension, high blood cholesterol, inflammatory gut conditions, and certain autoimmune diseases. The positive health effects are thoroughly explained in
The Revised Paleo Diet
(2010, John Wiley & Sons) and in
The Paleo Answer
(2012, John Wiley & Sons).