Written by Chris Masterjohn Phd
Do Fish Oils Prevent Heart Disease?
Researchers in the 1970s suggested that the high content of omega-3 fatty acids in the diet of the Greenland Inuit may have protected them from heart disease by lowering their cholesterol and triglyceride levels.75Since then, dozens of randomized, controlled trials have tested the effect of fish oil supplementation on total and cardiovascular mortality, discussed in more detail in the sidebar below. These studies suggested that about one gram of long-chain omega-3 fatty acids per day may prevent arrhythmia in patients prone to chronic heart failure or in patients recovering from a recent heart attack. They also suggested that long-term use of fish oils for more than four years may actually increase mortality from heart disease and all causes.
Many other groups eating traditional diets appear to be free or nearly free of heart disease, and a high intake of marine oils is not a universal trait of these diets. The main source of fat for the Masai, for example, is highly saturated butterfat. The inhabitants of Tokelau consume a diet based mostly on coconut and to a lesser extent on seafood, and even the seafood they prepare contains only two percent of its calories as long-chain omega-3 fatty acids.76 The inhabitants of Kitava consume about two percent of their total calories as omega-3 fatty acids,77 which is greater than the amount that Tokelauans consume but much lower than the amount that the Inuit consume.
The traditional diet of Crete provides most of its fat as saturated butterfat from cheese and as monounsaturated olive oil, and contains very little fish.78
If we are to offer a hypothesis about what protects all these groups from heart disease, we must first identify what their traditional diets share in common. The most obvious place to start is the complete absence of refined foods. A very high intake of marine oils, by contrast, is a specific peculiarity of the Inuit diet.
Back to Traditional Diets
Experimental evidence shows clearly that the requirement for essential fatty acids is infinitesimal under most conditions and can be easily met by eating a diet that includes traditional whole animal foods without necessarily adding any specific fats or oils. There is very little evidence to suggest that consuming higher amounts of these fatty acids under ordinary conditions is health-promoting.At the same time, many foods containing PUFAs provide other important nutrients.
The Inuit, for example, obtained vitamin D from fatty fish and marine oils. Inland-dwelling Inuit who did not have access to these foods were vulnerable to disorders of calcium deficiency.82 These included fits of involuntary muscle contractions called tetany, and a type of hysteria called pibloktoq in the native language. Pibloktoq involves several days of irritability or withdrawal, a sudden excitation wherein the victim flees the camp and engages in irrational and dangerous behavior, convulsive seizures, a twelve-hour period of coma or stuporous sleep, and a final return to normal. It would be absurd to argue that the Inuit should have avoided the fatty fish and marine oils that helped prevent these conditions simply because they provided omega-3 fatty acids in great excess of the amount needed to promote health.
The most common plant foods Weston Price mentions in Nutrition and Physical Degeneration are the banana and sweet potato, but he also reported the use of cereal grains and legumes among many groups, and other authors have reported the use of substantial amounts of nuts and seeds among the Australian Aborigines. These foods would provide an excess of linoleic acid, but would also provide a broad spectrum of other useful nutrients. All of the groups Price studied consumed organ meats, which reduces the risk of an imbalance between omega-3 and omega-6 fatty acids by providing preformed arachidonic acid and DHA, and may supply critical antioxidants necessary to protect excess PUFAs from oxidizing within the body. The use of a single component of these diets such as nuts and seeds or high-dose fish oil without the use of other components such as organ meats, however, may provoke the ravages of imbalanced PUFA intake and oxidative stress.
The need for essential fatty acids increases during childhood, bodybuilding, recovery from injury, chronic disease states, pregnancy and lactation. During these times, the use of foods such as liver and egg yolks from pasture-raised animals and small amounts of cod liver oil is especially important. Some individuals may, for unknown reasons, require higher intakes of essential fatty acids. Symptoms of deficiency are shown in Figure 6 and can be used to determine whether someone might benefit from increasing their intakes of these foods.
Rather than denouncing the essential fatty acids as “toxic” because they can promote inflammation or oxidative stress, they should be seen as delicate and precious nutrients that must be handled properly, taken in appropriate amounts, and taken within the context of a traditional diet rich in a broad spectrum of nutrient-dense foods. Within this context, the essential fatty acids will promote robust, radiant and vibrant health.
