Fatty Acids (FA)
There are twenty different fatty acids in our tissues. FA are chains of carbon molecules with the form:-C-C-C- A single bond -C-C-C- is "saturated". If carbon atoms are joined by two of their available four bonds -C=C=C- the FA is described as "unsaturated". Double bonds facilitate molecular re-arrangement and unsaturated fats with -C=C=C- have advantages that saturated bonds lack. The unique properties of each fatty acid are more important to know than general biochemical properties of groups of fatty acids. The disadvantage of unsaturated carbon bonds is that they are easily oxidized, and oxidized FAs tend to be toxic. If vegetable oils are cooked at high temperature in the frying pan or deep fryer, oxidation occurs rapidly. This is the argument against fried foods. Slow fat oxidation underlies rancidity of fat. Most oils are preserved with antioxidants to prevent rancidity. Careful manufacturers may supply sensitive oils in hydrogen-packed, black, sealed bottles and instruct you to store bottles in the fridge.
The general chemical formula of a fatty acid is:
Chain length varies from 1 to 24 carbon atoms and the carbon atoms are numbered from the COOH (the acid) end. The hydrocarbon chain may contain single and double bonds. A fatty acid with more than one double bond is described as a polyunsaturated fatty acid (PUFA).Double bonds occur every 3 carbon atoms. The current naming system uses number coding to show the length of the carbon chain, the number and position of the double bonds. Fatty acids are also divided into 4 groups, depending on the number of C atoms up to the first double bond, started at the other end, the omega end, of the chain. The omega-number refers to the location of the first unsaturated -C=C- bond from the omega end of the fatty acid chain.
The omega-3 group starts with alphalinolenic acid (ALA) found in the leaves and seeds of many plants. Longer chain omega-3 fatty acids are found in fish and marine animals (EPA and DHA).
The omega-6 group starts with linoleic acid (LA), and progresses to gamma-linoleic acid (GLA), di-homo-linoleic acid and then to arachidonic acid. Arachidonic acid (AA) is sometimes considered an essential FA but may be produced internally by the conversion of linoleic acid.
Oleic acid in olive oil is described as a "mono-unsaturate” because it has only one -C=C- bond rather than two or more. While not essential, it may be considered a desirable fatty acid.
The omega 3 series of FA are derived from alphalinolenic acid (18:3n-3). The major sources are flax seed, soybean, canola, wheat germ, and walnuts oils. The two most publicized long chain omega 3 FAs are: eicosapentaenoic acid (EPA) C20:5n-3 and docosahexaenoic acid (DHA) C22:6n-3). DHA is present in all tissues; 60% of the human brain is comprised of PUFAs, predominately DHA.
Linoleic acid (LA), the 18 carbon n-6 essential fatty acid, is found in canola, safflower, corn, soybean, and cottonseed oils. Meat products are a source of the n-6 fatty acid, arachidonic acid (AA) (C20:4n-6). GLA is synthesized from LA via an enzyme, delta-6 desaturase. Oils with higher GLA content have been derived from the seeds of evening primrose, borage and black currant.
Many articles have been written to recommend fish oil intake to prevent heart disease. Fish eaters suffer less cardiovascular disease. Eicosapentenoic acid (EPA) is mostly found in fish, especially salmon, herring, anchovies, mackerel, salmon, sardines, sea bass, swordfish, and trout. Some recommendations are to increase fish intake, while others recommend specific amounts of EPA and DHA as a supplement. Kris-Etherton stated that walnut, flaxseed, soybean, and canola oil can contribute to meeting ALA recommendations. A high intake of n-6 fatty acids, however, inhibits the conversion of ALA to EPA and DHA. Epidemiologic studies in the United States report that 500 mg/day of n-3 fatty acids can decrease CHD risk. The average diet only provides 100 mg EPA and DHA per day. Arterburn concluded that DHA is important to supplement, with or without EPA.
To saturate the plasma, 2 g DHA per day is needed for 1 month; to saturate the tissues, 3 to 6 months; and less than 1 week for DHA supplementation to increase human milk concentrations. To remain at saturation levels in the plasma, tissues, or human milk, continued supplementation is necessary.
Dwyer et al identified a subpopulation with increased atherosclerosis. They observed diet–gene interactions which lead to dietary n–6 polyunsaturated fatty acids promoting inflammation and marine n–3 fatty acids inhibiting inflammation. Leukotrienes are inflammatory mediators generated from arachidonic acid by the enzyme 5-lipoxygenase. They hypothesized that a polymorphism in the 5-lipoxygenase gene promoter could influence atherosclerosis and could interact with the dietary intake of different fats. They found 6 % of a study cohort had two variant gene alleles and had increased arterial wall thickness. Increased dietary arachidonic acid increased the atherogenic effect and increased dietary intake of n–3 fatty acids reduced the effect.
Another variable of fatty acid structure is that the double bonds may have one of two forms; cis and trans. Only the cis form functions normally. Animal fats tend to have some trans fatty acids. A high intake of trans fat increases the risk of coronary heart disease by increasing LDL cholesterol and decreasing HDL cholesterol. The American Heart Association guidelines recommend limiting the intake of saturated fat to 7% and trans fat to less than 1% of daily energy intake.
The hydrogenation of vegetable oils to make shortening, lard, and margarine produces trans fatty acids. These solid and semi-solid fats have largely replaced butter with its high content of saturated fatty acids as a baking and cooking ingredient. Two of the least desirable foods in a store are margarine and shortening. Trans fats are abundant in processed, boxed, bottled and fast foods. A wave of negative publicity has attracted regulators who first demanded a declaration of trans fat content on the nutritional label of foods sold in stores and more recently are proposing legislation to ban restaurant foods with high content of trans fats. The food industry has turned bad publicity into marketing opportunities. New labels boast of zero trans fats.
The Alpha Nutrition Program can be recommended, along with Alpha DMX, exercise and relaxation as a rational strategy of preventing and managing cardiovascular disease. The program is designed to reduce sodium, cholesterol, total fat, saturated fats, while increasing calcium, potassium, folic acid, omega 3 fatty acids and vegetable fiber. These are all desirable measures in the effort to prevent blood vessel diseases, heart attacks and strokes.
High Blood Pressure According to the Canadian Coalition for High Blood Pressure Prevention and Control, non-drug strategies should be the priority for hypertension control. Smoking cessation, low sodium, low fat diet, weight loss, exercise, reduced alcoholic beverage consumption, and increased calcium, magnesium and potassium intake are the important steps to avoid high blood pressure.
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