The Paleo Diet (20 page)

Peanuts are forbidden. As mentioned, they are not nuts at all; they’re legumes—and legumes contain lectins and other antinutrients that can adversely affect your health, particularly if you are suffering from an autoimmune disorder.

Important note: Many people are allergic to nuts, and pine nuts can be particularly troublesome for some people. Listen to your body carefully as you begin the Paleo Diet and fine-tune the diet to your specific health needs. Although nuts and seeds are true Paleo foods—and were certainly part of the diets of our ancient ancestors—they were not the staples.

When you shop for nuts:

Vegetable oils were obviously not a component of any pre-agricultural or hunter-gatherer diet, simply because the technology to produce them did not exist. Oils made from walnuts, almonds, olives, sesame seeds, and flaxseeds were first produced using crude presses between 5,000 and 6,000 years ago. However, except for olive oil, most early oil use was for nonfood purposes, such as illumination, lubrication, and medicine. It wasn’t until the beginning of the twentieth century, with the advent of mechanically driven steel expellers and hexane extraction processes, that vegetable oils started to contribute significantly to the caloric content of the Western diet. Today vegetable oils used in cooking, salad oils, margarine, shortening, and processed foods supply 17.6 percent of the total daily energy intake in the U.S. diet. The enormous infusion of vegetable oils into the Western diet, starting in the early 1900s, represents the greatest single factor responsible for elevating the dietary omega 6 to omega 3 ratio to its current and unhealthful value of 10 to 1. In hunter-gatherer diets, the omega 6 to omega 3 ratio was closer to 2 to 1. If we use the evolutionary template exclusively, vegetable oils should probably constitute a minimal part of modern-day Paleo diets.

So, if this is the case, why should we not eliminate all vegetable oils from our diet?

I still believe that certain oils can be used to cook with and add flavor when making condiments, dressings, and marinades. Simply stated, there are four oils (flaxseed, walnut, olive, and avocado) that can promote health and facilitate your getting the correct balance of good fats into your diet. Because hunter-gatherers ate the entire carcasses of wild animals (tongue, eyes, brains, marrow, liver, gonads, intestines, kidneys, and so on) and relished fatty plant foods (nuts and seeds), they did not have to worry about the correct balance of fatty acids in their diet. It came out correctly in the wash.

For most of us, the thought of eating organs is not only repulsive, but is also not practical as we simply do not have access to wild game. Consequently, by eating lean meats, fish, and seafood, along with healthful oils, nuts, and seeds, you can get the correct balance of fatty acids in your diet.

As you can see from the table on page 134, only three vegetable oils have omega 6 to omega 3 ratios of less than 3. These are flaxseed (0.24), canola (2.0), and mustard seed (2.6). Although I originally recommended mustard seed oil in the first edition of
The Paleo Diet
, I can no longer make this recommendation because of its high erucic acid (a long-chain monounsaturated fatty acid) concentration of 41.2 percent. Consumption of large quantities of erucic acid in laboratory animals causes adverse changes in their heart structure and function and other organs.

This leaves only two vegetable oils (canola and flaxseed) that do not contribute to an elevated intake of omega 6 fatty acids. A number of epidemiological (population) studies have shown a higher risk of developing prostate cancer with an increased consumption of alpha linolenic acid (ALA), a major fatty acid found in both canola and flaxseed oil. However, epidemiological studies are notorious for their conflicting results. For every six studies that support one nutritional concept, you can often find half a dozen more that conclude precisely the opposite. Such is the case linking ALA and flaxseed oil to an increased prostate cancer risk. A series of the most recent epidemiological studies was unable to statistically show that ALA consumption increased prostate cancer risk. More important, in experiments in which animals were fed flaxseed oil, the flaxseed actually inhibited the growth and development of prostate cancer. The case supporting flaxseed oil as a promoter of prostate cancer is currently based solely on epidemiological evidence and therefore remains inconclusive because of the total lack of confirming experimental evidence. Because the majority of epidemiological studies support the notion that ALA is protective against cardiovascular disease, flaxseed oil should still be viewed as healthful.

Since the original publication of
The Paleo Diet
in 2002, I have reversed my view of canola oil and can no longer support its consumption or use. Let me explain why. Canola oil comes from the seeds of the rape plant (
Brassica rapa
or
Brassica campestris
), which is a close relative of broccoli, cabbage, Brussels sprouts, and kale. Clearly, humans have eaten cabbage and its relatives since prior to historical times, and I still strongly support the consumption of these health-promoting vegetables. The concentrated oil from the seeds of
Brassica
plants is another story.

In its original form, rape plants produced a seed oil that contained high concentrations (20 to 50 percent) of erucic acid (a monounsaturated fatty acid labeled 22:1n9), which I have previously explained is toxic and which causes a wide variety of pathological changes in laboratory animals. In the early 1970s, plant breeders from Canada 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 content of commercially available canola oil averages 0.6 percent. Despite its low erucic acid content, however, a number of experiments in the 1970s showed that even at low concentrations (2.0 percent and 0.88 percent), canola oil fed to rats could still produce minor heart scarring that was considered “pathological.”

A series of recent rat studies of low-erucic canola oil conducted by Dr. Ohara and colleagues at the Hatano Research Institute in Japan reported kidney injuries, as well as increases in blood sodium levels and abnormal changes to a hormone, aldosterone, that regulates blood pressure. Other negative effects of canola oil consumption in animals at 10 percent of calories include decreased litter sizes, behavioral changes, and liver injury. A number of recent human studies of canola/rapeseed oil by Dr. Poiikonen and colleagues at the University of Tempere in Finland have shown it to be a potent allergen in adults and children and indicate that it may cause allergic cross-reactions from other environmental allergens in children with atopic dermatitis (skin rashes).

Based on these up-to-date studies in both humans and animals, I prefer to be on the safe side and can no longer recommend canola oil.

Both olive oil and avocado oil are high (73.9 and 70.6 percent, respectively) in cholesterol-lowering monounsaturated fatty acids but have less than favorable omega 6 to omega 3 ratios of 11.7 and 13.5. Consequently, excessive consumption of both of these oils without adequate intake of long-chain omega 3 fatty acids (EPA plus DHA) will derail an otherwise healthy diet. I recommend that you get 1.0 to 2.0 grams of EPA and DHA per day in your diet from either fish or fish oil capsules. Because avocado oil is difficult to find and expensive, that pretty much leaves olive oil as the staple for cooking, salad dressings, and marinades.

If you can afford it, I recommend that you always choose extra-virgin olive oil, because this grade of oil is produced by physical means only, without chemical treatment, and it contains the highest concentrations of polyphenolic compounds, which protect against cancer, heart disease, and inflammation.

Although peanut oil has been promoted as a healthy, cholesterol-lowering oil because of its high monounsaturated fat content (46 percent of total fat), it has turned out to be one of the most atherogenic (artery-clogging) of all oils. In fact, it is routinely used to induce coronary artery atherosclerosis in monkeys and other laboratory animals. It’s not clear exactly why this happens. Some scientific evidence suggests that peanut lectins (proteins that bind to carbohydrates) may be responsible for this effect.

Because soybean oil also contains residual lectin activity (SBA) and maintains a marginal (7.5) omega 6 to omega 3 ratio, it can’t be recommended as a staple oil, either. A similar argument can be made for wheat germ oil, which has a marginal omega 6 to omega 3 ratio of 7.9 but also contains large quantities of the lectin WGA, one of the most widely studied and potentially most damaging of all the dietary lectins.

Coconut meat, oil, and milk are traditional foods of indigenous people who live in the tropics. These foods have high amounts of a saturated fat called lauric acid, which is known to elevate blood cholesterol concentrations—a risk factor for cardiovascular disease in modern Westernized populations. Paradoxically, traditional cultures that consume coconut foods have a minimal or nonexistent incidence of heart disease, stroke, or cardiovascular complications normally associated with eating high levels of saturated fats, such as the lauric acid found in coconut food products.

Lauric acid apparently exerts a protective effect in our bodies by eliminating gut bacteria that increase intestinal permeability, a risk factor for cardiovascular disease via heightened chronic low-level inflammation. Based on the evidence of traditional Pacific Islanders who consume coconut, it appears that this food does not present a risk for cardiovascular disease when included as a component of modern Paleo Diets. Let your palate go back to the islands and enjoy the delicious health benefits of this traditional plant food.

One of the key elements of the Paleo Diet is to cut way down on your use of salt—or, better yet, cut it out entirely. This doesn’t mean you need to eat bland, tasteless food—far from it. If you haven’t already plunged into the wonderful world of spices, now’s your chance.

Lemon crystals and lemon pepper are good replacements for salt, and they give food a mouthwatering zing. There are also several good salt substitutes, commercially available spice mixes designed to take the place of salt. Note: Check the labels; sometimes spice mixes contain cornstarch, hydrolyzed wheat proteins, or other grain and legume products.

Some people—particularly if they are suffering from an autoimmune disease—should stay away from spices made from chili peppers (cayenne pepper and paprika). This botanical family of spices contains a substance called “capsaicin.” Studies by Dr. Erika Jensen-Jarolim and colleagues at University Hospital in Vienna, Austria, have shown that capsaicin increases intestinal permeability and may play a role in the development and progression of certain autoimmune diseases. Again, let your body serve as your guide: if a spice seems to be irritating your system or causing problems, don’t use it.

The good news is that most spices are easily digestible and well tolerated and add subtle flavors and overtones to almost all dishes. They’ll make your food come alive.

The starting point for the optimal Paleo Diet lies in our genes. In some respects, we’re all the same. We’ve all got the basic human genome, shaped by more than 2 million years of evolution and adapted to eat lean, wild animal meats and uncultivated fruits and vegetables. But we’re all different, too. Our own genetic differences ultimately influence how we react to certain foods or food types, or how much of a particular nutrient, vitamin, or mineral we need to maintain good health. Even though seafood should be a central part of the Paleo Diet, for example, it’s clearly out of the question for people who are allergic to it. If you have a nut, shellfish, or other food allergy, then obviously these foods cannot be part of your individualized program.

The National Academy of Sciences has provided DRIs (Dietary Reference Intakes) for vitamins and minerals. However, these one-size-fits-all guidelines aren’t necessarily perfect for everyone. For example, people who are exposed to extra environmental pollutants (say, cigarette smoke) have been shown to require extra antioxidant vitamins. Certain diseases and disorders are known to impair the body’s ability to absorb nutrients; pregnant women and breast-feeding mothers need more nutrients than other women do.