Balancing EFAs and Anti-Oxidants.
Because EFAs are polyunsaturated, containing two or more double chemical bonds, they are prone to rancidity, not merely in foods but also in the human body. Rancidity occurs when the double bond is broken by oxygen, producing an oxidized fatty acid. Oxidized fatty acids not only taste badly, they behave badly, disrupting the normal functioning of the cell membranes of which they are a part. Oxidized fatty acids are rapidly generated from the process called free radical-induced cell damage.
To protect EFAs from harmful oxidation, it is essential to consume adequate levels of dietary anti-oxidants, especially vitamin E. Consumption of a nutrient-dense diet will assure a higher-than-average intake of all anti-oxidants. Depend-ing upon the specific foods chosen, however, where those foods have been grown, the efficiency of digestion and absorption, the need for EFA supplementation, and the pres-ence of inflammation within the body, supplementation of the diet with additional anti-oxidants may be necessary. For people who supplement their diets with fish oils or flax oil, a minimum anti-oxidant supple-ment should include vitamin E (four hundred units per day), selenium (one hundred micrograms per day), and vitamin C (one thousand milli-grams per day), in addition to--not instead of--a nutrient-dense diet.
TRANS FATTY ACIDS AND HYDROGENATED OILS
The dangers of trans-fatty acids in the diet have recently received scientific attention that is long overdue. To understand the toxic potential of trans-fatty acids, you have to know how they effect the body's use of EFAs.
EFAs have a chemical structure which is polyunsaturated. Technically, this means that each molecule of an EFA has two or more double chemical bonds. The double bonding twists the mole-cule, giving it a serpentine shape. When incorporated into a cell's membranes, the snake-like EFA molecules add fluidity and flexibility to the membrane. EFAs, unfortunately, are rather unstable when exposed to air. The double bonds break down rapid-ly, producing a toxic form of fat that can be detected in food by its rancidity. Preservatives may be added to food to prevent this breakdown from occurring, thereby increasing the shelf-life of the food. A natural preservative for fatty acids is vitamin E (alpha-tocopherol), but the most commonly used preservatives are the synthetic anti-oxidants, BHT and BHA.
A more efficient way to prolong shelf-life, however, is to hydrogenate the fatty acids, destroying the EFAs. In hydrogena-tion, the double bonds are broken by hydrogen gas and the unsatu-rated fatty acids become saturated with hydrogen. This means that all sites for chemical bonding are filled. Natually saturated fatty acids are commonly consumed in meat and dairy products. They are also manufactured in your liver and stored in your body's fat cells. Saturated fatty acids are straight, not twist-ing, in shape, and impart stiffness and solidity to mem-branes. Human cell membranes usually have one saturated fatty acid lined up along-side one unsaturated fatty acid, producing just the right blend of stiff-ness and flexibility for responding properly to signals sent from other cells.
In present-day food processing, the hydrogenation of vegeta-ble oils is usually not complete. It is partial. Par-tially hydrogenated oils are easier to work with and produce a softer foodstuff than fully hydrogenated oils. Chemically, partial hydrogenation converts EFAs into trans-fatty acids, which are unsaturated fatty acids that twist abnormally. Trans-fatty acids do not have the serpentine shape and fluidity of naturally unsaturated fatty acids (which are called cis-fatty acids). Trans-fatty acids are stiff and straight, like saturated fatty acids, but, because they are unsaturated, they replace natural cis-fatty acids in the cell membranes. The result of trans-fatty acid consumption is stiff cell membranes, abnormal response to signals from other cells, and an increase in dietary requirements for EFAs. Partially hydrogenated vegetable oils, which are unbiquitous in manufactured foods, are loaded with these anti-nutrients.
In the first edition of Superimmunity for Kids, written ten years ago, I warned parents about the dangers of raising their children on margerine and other foods built from partially hydrogenated oils. My arguments derived from research on the chemical effects of trans-fatty acids and knowledge of how this chemistry could distort cell function. Clinical studies have vindicated the warning. High consumption of trans-fatty acids raises cholesterol levels and increases the risk of heart attack, especially among women. Dr. Walter Willett, chairman of the Department of Nutrition at Harvard University's School of Public Health, estimates that consumption of trans-fatty acids in the United States accounts for thirty thousand premature deaths per year. Hydrogenated vegetable oils containing trans-fatty acids have no place in a healthy diet and should be avoided by everyone.