|LE Magazine July 2001|
Fats for Life
Page 1 of 4
Imagine a kind of fat that could help reduce cholesterol levels, lower blood pressure, fight dementia and slow down the aging process. This fat would be better than any known drug. Best of all, it is not a fantasy but a reality. We are talking about certain polyunsaturated, natural fatty acids, whose beneficial effects have been documented in thousands of studies over the last decade. Of crucial importance, however, is taking the right essential fatty acids in the correct balance.
Years of conflicting messages about the role of fat in our diet have caused much confusion and even skepticism toward new information. In spite of scientific progress, few commercial messages today are based on current scientific knowledge. Instead they are deliberate half-truths and misinformation from companies eager to sell their “fat-free” and “cholesterol-free” products. Hidden are the facts that the sugar and hydrogenated fats in their products are the real culprits that will increase the body’s own production of cholesterol or other unhealthy fats, causing exactly the damage thought to be avoided.
Fat is necessary for life. It is a key component in body chemistry and energy storage. Knowing the difference between the beneficial essential fatty acids (EFAs) and the harmful fats is of crucial importance for health and longevity. Extensive research has made it clear that a reduced or imbalanced intake of EFAs plays a significant role in the development of many cardiovascular, neurological, metabolic and other age-related degenerative diseases.
This research has singled out two particularly beneficial fatty acids, GLA and DHA, and pointed to an ideal balance between them that could guard against disease and age-related disorders in many-fold ways. These key fatty acids protect the cardiovascular system, lowering blood pressure, raising good (HDL) cholesterol while lowering bad (LDL) cholesterol and triglyceride levels. They reduce stress reactions, and may ameliorate insulin resistance. GLA helps reverse the effects of aging on fatty acid metabolism, while DHA is essential to the development and maintenance of brain functions, being of crucial importance for children, as well as for the elderly in prevention and treatment of dementia.
The richest known source of GLA is borage oil (23% GLA), while DHA is plentiful in cold water fish. GLA and DHA make a wonderful team for health and longevity.
Omega-3 and omega-6 oil
Fatty acids serve as building blocks of nerve cells, cell membranes and biochemical messengers such as prostaglandins. Essential fatty acids (EFAs) cannot be produced within the body and therefore must be provided through the diet. If the diet is lacking in EFAs, saturated fats will take the place of EFAs within cell membranes, reducing membrane fluidity and efficiency, and thereby starting a process of premature aging and disease development. In addition, by taking the right kinds of EFAs in the right proportions, we can maximize the production of beneficial prostaglandins and other chemical messengers, while minimizing production of harmful ones.
Getting the omega-6 and omega-3 fatty acids in the right proportions can reduce bad LDL cholesterol and raise good HDL cholesterol
There are two families of EFAs: omega-3 and omega-6 fatty acids. Experimental studies confirm that a balanced combination of these two families is essential for maximal effect in lowering blood pressure, improving the serum lipid profile and reducing atherosclerosis. When dietary omega-6 and omega-3 oils were used separately and in combination in a study on the regression of experimental atherosclerosis in rabbits, cholesterol levels decreased faster in the group fed the combination oils. In this group there was also a three-fold reduction of atherosclerotic plaques in the aorta compared to untreated animals (Khalilov et al., 1997).
An ambitious study of different ratios and dosages of EFAs, given to 20 Vervet monkeys over a 12 weeks period, documented the importance of getting these essential fatty acids in the right proportion. The results indicate that a combination of omega-6 and omega-3 (in this case, GLA and EPA), in a proportion ranging from 2:1 to 4:1 (two to four parts of omega-6 to one part of omega-3), is the ideal combination to reduce bad LDL cholesterol, raise good HDL cholesterol and thus improve the LDL/HDL cholesterol ratio (van Jaarsveld et al., 1997).
This finding conforms with recommendations by a number of health agencies around the world, including the World Health Organization, the British Nutrition Foundation and the Japan Society for Lipid Nutrition. Based on evidence that an elevated ratio of omega-6 to omega-3 fatty acids is a major risk factor for many chronic diseases, these agencies recommend a ratio ranging from approximately 2:1 to 4:1 (Horrocks et al., 1999). Due to the disproportionate level of omega-6 oils in the typical American diet, it is preferable to supplement at the lower end of this range, at a ratio of two parts omega-6 to one part omega-3 oils.
GLA & DHA
To express their full biological activity, the two “parent” EFAs, linoleic acid (omega-6) and alpha-linolenic acid (omega-3) must be metabolized in several steps with the help of important enzymes. In this process GLA (gamma-linolenic acid) is produced from linoleic acid, and DHA (docosahexaenoic acid) as well as EPA (eicosapentaenoic acid) from alpha-linolenic acid. The high ratio of linoleic acid (omega-6) to alpha-linolenic acid (omega-3), typically found in western diets, will inhibit both the uptake and the conversion of alpha-linolenic acid due to competition for the same enzymes between the two EFAs.
The Good and Bad
Too much prostaglandin E2 can lead to degenerative disease, whereas high levels of beneficial pros-taglandin E1 and E3 protect the body. Here is a brief description of how these prostaglandins function in the body:
• Prostaglandin E1 prevents blood platelets from sticking together, thereby helping to prevent heart attacks and strokes caused by blood clots. It relaxes blood vessels, improving circulation and lowering blood pressure. It reduces inflammation, makes insulin work more effectively and enhances the T-cell function of the immune system. GLA increases this beneficial prostaglandin.
• Prostaglandin E2 promotes platelet aggregation, the first step to clot formation, increasing the risk for heart attack and stroke. It makes the kidneys retain sodium, leading to water retention, and it causes inflammation. Diets high in saturated fats (arachidonic acid) increase levels of this pro-inflammatory prostaglandin.
• Prostaglandin E3 has similar functions as prostaglandin E1. It also has a powerful effect of preventing the release of arachidonic acid stored in cell membranes and its conversion to prostaglandin E2. Omega-3 fatty acids are the source of this beneficial prostaglandin.
The first step in both these conversion processes is controlled by the enzyme D6D (delta-6 desaturase). Unfortunately, D6D activity declines with age, and is reduced in some individuals even at a younger age (Horrobin, 1981). This not only inhibits the synthesis of GLA and DHA, but also leads to a prostaglandin imbalance with decline of the good series-1 and series-3 prostaglandins and other beneficial eicosanoids, which exhi-bit potent anti-inflammatory and immunoregulatory effects. The reduced capacity to convert parent EFAs to GLA and DHA is associated with conditions including cardiovascular disease, diabetes, alcoholism, atopic dermatitis, premenstrual syndrome, rheumatoid arthritis and cancer (Bolton-Smith et al., 1997; Leventhal et al., 1993; Horrobin, 1993), as well as learning deficits and development of dementia.
The exciting news is that supplementation with GLA and DHA can circumvent impaired D6D function, and restore levels of the good prostaglandins. Moreover, GLA supplementation actually increases D6D activity, reversing the effect of aging on the enzyme itself (Biagi et al., 1991). In this way, GLA supplementation improves the meta-bolism of both omega-6 and omega-3 fatty acids. It has also become clear that the omega-3 fatty acids DHA and EPA limit the production of the bad series-2 prostaglandins by preventing the release of arachidonic acid from cell membranes, inhibiting its further metabolism. A high amount of linoleic acid (omega-6), on the other hand, limits the availability of alpha-linolenic acid (omega-3) as a precursor for the good series-3 prostaglandins and stimulates the formation of arachidonic acid, the precursor to the bad prostaglandins (series-2) and other pro-inflammatory eicosanoids.
Biagi et al. (1991) studied both old and young rats that were fed either a GLA-rich diet or a control diet. Old animals fed the control diet showed a clear decline in the level of delta-6-desaturated meta-bolites of both the omega-6 and the omega-3 series. In the GLA group of old mice there was no decline of these metabolites.
A study of more than 10,000 middle-aged men and women in Scotland showed that aging influences the fatty acid composition of adipose (fatty) tissue independently of diet (Bolton-Smith et al., 1997). The study confirms the earlier mentioned experimental findings of an age-related decline in the rate-limiting step of delta-6-desaturation, and in addition discovered a greater decline in women than in men. The results indicate that an increase in dietary GLA could offset the age-related imbalance in fatty acid levels.
GLA and DHA both have preventive effects on atherosclerosis and heart attacks by lowering blood pressure and serum lipids and reducing cardiovascular reactions to stress. While GLA in addition has anti-aging effects, DHA has a unique role in the development and maintenance of the nervous system. It has proven to be important for development, learning and behavior in children as well as for prevention and treatment of dementia.
Beneficial effects of both GLA and DHA on the cardiovascular system have been extensively documented in experimental and human studies: moderate but consistent blood pressure lowering effects, significant reductions of serum lipids, and beneficial influence on insulin resistance which plays a large role in the development of diabetes, atherosclerosis and heart attacks. Much research is currently focused on unraveling the many-fold mechanisms of action behind these favorable influences.
Early detection is of great importance, since life style changes as well as medication is likely to prevent further development of serious complications. Incorporation of GLA and DHA in the diet has proven to be one of these changes that can reduce the blood pressure and help lower the risk of heart attacks, stroke and kidney failure.
Borage oil and DHA have blood pressure lowering effects
In contrast to earlier beliefs, we now know that a stable systolic blood pressure (below 140 mmHg) is equally or even more important than a “normal” diastolic pressure (less than 90 mmHg). Systolic blood pressure increases with aging as a result of increased stiffness of the arteries and is a stronger predictor of risk in the elderly than the diastolic pressure. A pulse pressure (the difference between systolic and diastolic pressure) of more than 60 is a marker for advanced atherosclerosis and indicates a high risk for a cardiovascular event.
In most cases of hypertension (95%) no specific reason can be found for the elevated pressure, a condition known as essential or idiopathic hypertension. Results from a clinical, double blind, crossover study by Venter et al. (1988) support the hypothesis that deficiency of the enzyme D6D, so common in aging, may play an important part in the etiology of idiopathic hypertension. The study furthermore validates the earlier findings that a ratio of 2:1 of GLA and DHA/EPA is beneficial in prevention of cardiovascular diseases.
This trial involved 25 non-obese patients with mild-moderate essential hypertension. One group was given capsules containing 360 mg GLA and 180 mg EPA/day, while the other group received capsules containing only linoleic acid and alpha-linolenic acid, the parent EFAs that need the enzyme D6D for their metabolism to GLA and EPA/DHA. The average systolic blood pressure in the first group was significantly reduced (~ 10 %) after 8 to 12 weeks of therapy, while there was no significant change in the second group, indicating that deficiency of the enzyme D6D is likely to promote an increase of blood pressure.
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