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| Nutraceuticals and Herbal Remedies |
Some FDA-approved supplements and preventions or treatments include calcium and osteoporosis, fiber-containing grain products, fruits and vegetables and cancer, and folate and neural tube birth defects. Listed below are some foods or food ingredients that are commonly marketed for their medical benefits.
OLIVE OIL
The typical Mediterranean diet, rich in olive oil, has been found to be associated with lower levels of cholesterol and triglycerides, and lower blood pressure then many other diets. Diets enriched with oleic acid, the main fatty acid in olive oil, have been shown to significantly reduce both total cholesterol and the harmful form of cholesterol (low-density lipoprotein, LDL) as well as total triglyceride levels, while the beneficial form of cholesterol (high-density lipoprotein, HDL) levels remain unchanged or are slightly increased. Oxidation of LDL cholesterol is involved in the formation of fat deposits in the arteries and ultimately atherosclerotic lesions. These lesions appear to hinder the ability of the blood vessels to dilate or relax upon certain signals. The high content of oleic acid in olive oil causes LDL cholesterol to become enriched in this fatty acid, making them more resistant to oxidation.
Additional benefits have been associated with consumption of olive oil or oleic acid. Diets containing high amounts of monounsaturated fatty acid (MUFA) including oleic acid have been shown to protect against mental decline in old age. A change from consumption of polyunsaturated to monounsaturated fats in the diet of certain diabetics increased their sensitivity to insulin and allowed easier control of their blood sugar levels. Preliminary results indicate a beneficial effect in the prevention of blood clots and in the lowering of high blood pressure.
In addition to oleic acid, other beneficial compounds are present in olive oil. Several phenolic compounds have antioxidant activities. Olive oil contains high amounts of squalene, a compound that inhibits a key enzyme in cholesterol synthesis and also may have tumor-inhibitory activity by inhibiting cancer signaling through the ras oncogene. Mutated ras oncogene activation may be important in many cancers, including cancer of the breast, colon and pancreas.
Additional benefits have been associated with consumption of olive oil or oleic acid. Diets containing high amounts of monounsaturated fatty acid (MUFA) including oleic acid have been shown to protect against mental decline in old age. A change from consumption of polyunsaturated to monounsaturated fats in the diet of certain diabetics increased their sensitivity to insulin and allowed easier control of their blood sugar levels. Preliminary results indicate a beneficial effect in the prevention of blood clots and in the lowering of high blood pressure.
In addition to oleic acid, other beneficial compounds are present in olive oil. Several phenolic compounds have antioxidant activities. Olive oil contains high amounts of squalene, a compound that inhibits a key enzyme in cholesterol synthesis and also may have tumor-inhibitory activity by inhibiting cancer signaling through the ras oncogene. Mutated ras oncogene activation may be important in many cancers, including cancer of the breast, colon and pancreas.
OAT BRAN
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| Herbal Remedies |
When combined with water, oat bran swells and forms a gum, which increases stool weight and may provide a bulk-forming laxative effect. Sufficient water must be consumed along with the oat bran to prevent constipation or blockage of the bowel.
LECITHIN
Lecithins are a type of phospholipid that are important components of cell membranes and are involved in fat digestion in the intestine. The protective sheaths surrounding the brain and nerve cells also contain these phospholipids. Lecithins are composed of a phosphate group, a choline group and two fatty acids (such as linoleic acid and linolenic acid). Since the two fatty acids can vary, different forms of lecithin exist.
Food sources of lecithins include soybeans, egg yolks, liver, wheat germ, and peanuts. Lecithins are often added to pharmaceutical, cosmetic and food industries to serve as stabilizing and emulsifying agents, allowing two different substances, like oil and water, to blend together.
Choline is a building block of acetylcholine, in important transmitter of signals among certain nerves in the brain and throughout the body. Lecithin supplements have been used in an attempt to increase brain acetylcholine and improve mental function in conditions such as Alzheimer’s disease. Clinical trials have failed to verify this benefit. Studies have also failed to demonstrate a significant benefit of lecithin supplements on certain movement disorders.
When applied to the skin, lecithin preparations are effective as moisturizing agents and are used in the treatment of dry skin. The benefits of oral supplementation remain to be proven. Although some studies have suggested lecithin supplementation may help lower high cholesterol levels, other studies disagree. However, the plant sterol sitostanol emulsified in a lecithin preparation appears to reduce cholesterol absorption in humans. Another study in mice indicated lecithin had a preventive effect against lung cancer. Lecithin supplements are generally well tolerated, however in some individuals they can cause diarrhea, nausea, abdominal pain and fullness. Persons on calorie-restricted diets should consider their high caloric content.
Food sources of lecithins include soybeans, egg yolks, liver, wheat germ, and peanuts. Lecithins are often added to pharmaceutical, cosmetic and food industries to serve as stabilizing and emulsifying agents, allowing two different substances, like oil and water, to blend together.
Choline is a building block of acetylcholine, in important transmitter of signals among certain nerves in the brain and throughout the body. Lecithin supplements have been used in an attempt to increase brain acetylcholine and improve mental function in conditions such as Alzheimer’s disease. Clinical trials have failed to verify this benefit. Studies have also failed to demonstrate a significant benefit of lecithin supplements on certain movement disorders.
When applied to the skin, lecithin preparations are effective as moisturizing agents and are used in the treatment of dry skin. The benefits of oral supplementation remain to be proven. Although some studies have suggested lecithin supplementation may help lower high cholesterol levels, other studies disagree. However, the plant sterol sitostanol emulsified in a lecithin preparation appears to reduce cholesterol absorption in humans. Another study in mice indicated lecithin had a preventive effect against lung cancer. Lecithin supplements are generally well tolerated, however in some individuals they can cause diarrhea, nausea, abdominal pain and fullness. Persons on calorie-restricted diets should consider their high caloric content.
GREEN TEA
Tea is made from the dried leaves and leaf buds of the shrub Camellia sinensis. Black tea is prepared by drying and fermenting the leaves and is consumed in many parts of the world. Oolong tea is partially fermented and is mainly consumed in China and Japan. Green tea, which is not fermented, is made by steaming or pan-frying tea leaves and then drying them. It is mainly consumed in China and Japan, where it has been used for its medicinal properties for about 5000 years.
Dried tea leaves contain polyphenols, including flavonols such as catechins, flavonoids and flavondiols. The leaves also contain the stimulants caffeine, theobromine and theophylline. The composition of green tea varies with the geographic origin of the leaf, the time of harvest and the manufacturing process. Fermentation of black tea lowers the concentration of polyphenols, and thus may decrease the health promoting effects associated with green tea. For this reason, there has recently been an increased interest in green tea consumption in the western world.
Many of the studies linking green tea to anticancer activity have highlighted a role in the prevention of certain types of cancer. Green tea consumption has been associated with a potential to decrease the risk of developing certain precancerous polyps in the colon, esophageal cancer in women, and pancreatic cancer. In animal studies it has also been shown to have a preventive effect in lung, liver, duodenal, and breast cancer. Part of the anticancer activity of green tea is thought to be due to the activity of the catechin epigallocatechin gallate (EGCG) and several similar substances. EGCG has antioxidant activity, but it may also deter cancer by inhibiting enzymes involved in cell division and DNA synthesis, or by inhibiting communication pathways in a cell that are required for cell division. These polyphenolic compounds may also prevent activation of certain potential cancer causing compounds that are ingested in the diet. The effect of tea consumption on cancer is likely to depend on the factors associated with a specific cancer. Therefore, a protective effect observed on one type of cancer within a given population may not be seen with cancer of a different type.
Scientific studies have suggested a preventive effect of green tea against the risk of stroke, atherosclerosis (hardening of the arteries), heart disease, high blood cholesterol levels, and high blood pressure. One mechanism by which green tea constituents lower cholesterol is by increasing fecal excretion of cholesterol. Another beneficial mechanism is the prevention of low-density lipoprotein (LDL) oxidation, a process involved in cholesterol deposition in blood vessels leading to atherosclerosis.
Although lower in caffeine content than black tea and coffee, green tea contains approximately 60 mg per cup and multiple cups per day can cause gastric hyperacidity and upset, constipation, diarrhea, restlessness, palpitations and difficulty sleeping. Many studies suggesting the healthful effects of green tea have been conducted in laboratory animals and these findings need to be confirmed in humans. In general, however, green tea is very well tolerated and many people may benefit from adding this beverage to their diet.
Dried tea leaves contain polyphenols, including flavonols such as catechins, flavonoids and flavondiols. The leaves also contain the stimulants caffeine, theobromine and theophylline. The composition of green tea varies with the geographic origin of the leaf, the time of harvest and the manufacturing process. Fermentation of black tea lowers the concentration of polyphenols, and thus may decrease the health promoting effects associated with green tea. For this reason, there has recently been an increased interest in green tea consumption in the western world.
Many of the studies linking green tea to anticancer activity have highlighted a role in the prevention of certain types of cancer. Green tea consumption has been associated with a potential to decrease the risk of developing certain precancerous polyps in the colon, esophageal cancer in women, and pancreatic cancer. In animal studies it has also been shown to have a preventive effect in lung, liver, duodenal, and breast cancer. Part of the anticancer activity of green tea is thought to be due to the activity of the catechin epigallocatechin gallate (EGCG) and several similar substances. EGCG has antioxidant activity, but it may also deter cancer by inhibiting enzymes involved in cell division and DNA synthesis, or by inhibiting communication pathways in a cell that are required for cell division. These polyphenolic compounds may also prevent activation of certain potential cancer causing compounds that are ingested in the diet. The effect of tea consumption on cancer is likely to depend on the factors associated with a specific cancer. Therefore, a protective effect observed on one type of cancer within a given population may not be seen with cancer of a different type.
Scientific studies have suggested a preventive effect of green tea against the risk of stroke, atherosclerosis (hardening of the arteries), heart disease, high blood cholesterol levels, and high blood pressure. One mechanism by which green tea constituents lower cholesterol is by increasing fecal excretion of cholesterol. Another beneficial mechanism is the prevention of low-density lipoprotein (LDL) oxidation, a process involved in cholesterol deposition in blood vessels leading to atherosclerosis.
Although lower in caffeine content than black tea and coffee, green tea contains approximately 60 mg per cup and multiple cups per day can cause gastric hyperacidity and upset, constipation, diarrhea, restlessness, palpitations and difficulty sleeping. Many studies suggesting the healthful effects of green tea have been conducted in laboratory animals and these findings need to be confirmed in humans. In general, however, green tea is very well tolerated and many people may benefit from adding this beverage to their diet.
FISH OIL
Fish Oil contains the omega-3 fatty acids eicosapentanoic acid (EPA) and docosahexanoic acid (DHA). These substances can compete for the formation of naturally occurring arachidonic acid in the production of several classes of biologically active substances, the prostaglandins, the thromboxanes and the leukotrienes. Some of these substances are involved in blood clotting, inflammation, and dilation of the blood vessels, hence their activities of decreased blood clotting, providing modest symptomatic relief in rheumatoid arthritis, lowering relapse rate in Crohn’s disease, decreasing inflammation in ulcerative colitis, decreasing pain associated with menstruation, and moderately lowering blood pressure. Fish oil supplements also lower blood triglycerides that can play a role in pancreatitis and cardiovascular disease.
Common side effects of fish oil include a fishy taste and belching. Large doses can cause loose stools. Simultaneous use with other drugs and herbs that decrease blood clotting ability such as anticoagulants (blood thinners), aspirin, fever, garlic, red clover and willow increase the risk of bleeding. Fish oil should be avoided in people with aspirin sensitivity as it may interfere with lung function and cause impaired breathing.
Common side effects of fish oil include a fishy taste and belching. Large doses can cause loose stools. Simultaneous use with other drugs and herbs that decrease blood clotting ability such as anticoagulants (blood thinners), aspirin, fever, garlic, red clover and willow increase the risk of bleeding. Fish oil should be avoided in people with aspirin sensitivity as it may interfere with lung function and cause impaired breathing.
GARLIC
Many alternative medicine advocates or folkloric remedies recommend garlic to lower cholesterol. Although garlic seems to inhibit cholesterol synthesis by the body, recent studies suggest that garlic supplements may not lower cholesterol. Garlic is composed of many sulfur containing compounds, including allinin. When garlic is crushed, allinin is converted to allicin and it is the allicin that effects cholesterol synthesis. In addition to the variability of allinin content, supplements do not contain all of the compounds found in fresh garlic. Therefore, it is not known if consumption of fresh garlic is required to have a cholesterol lowering effect.
Garlic used for cooking is generally safe, but large amounts in supplements can increase the effects of anticoagulants (blood thinners), therefore increasing the tendency for bleeding and can also interfere with blood sugar control in diabetics. Further studies are required before conclusions can be made.
Garlic used for cooking is generally safe, but large amounts in supplements can increase the effects of anticoagulants (blood thinners), therefore increasing the tendency for bleeding and can also interfere with blood sugar control in diabetics. Further studies are required before conclusions can be made.
SOY
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| Nutraceuticals |
The FDA has approved the claim that consumption of 25 g/day of soy protein (contained in 2-4 servings of a soy product) in combination with a diet low in saturated fat and cholesterol may reduce the risk of heart disease. Some of the key mechanisms by which soy protein may have a protective effect for the cardiovascular system include prevention of smooth muscle proliferation in the blood vessels, reduction of platelet aggregation (involved in blood clotting ability), blood-pressure reduction, and antioxidant effects on blood lipids. Studies also suggest that soy can lower cholesterol levels by approximately 10%, but this value is highly variable.
The most widely publicized of the biologically active components of soy are the isoflavones such as genistein and daidzein. They are considered phytoestrogens (plant products with estrogenic activity), but in certain conditions they can act as antiestrogens by blocking more potent estrogens. There is much controversy regarding the activity of isoflavones as cancer preventive or cancer stimulating compounds in estrogen sensitive tissues like the breast. It is generally recommended that women who are at an increased risk for breast cancer avoid isoflavone supplements.
Due to their estrogenic activity, the use of soy supplements has been proposed for several other conditions. For example, supplements has been anecdotally recommended for the relief of menopausal associated hot flashes, but several studies have drawn conflicting conclusions as to this effect. Hormone replacement therapy is a much more effective treatment for hot flashes. Preliminary findings suggest that soy protein or isoflavones may have a beneficial effect on maintaining bone density. Genistein may inhibit the bone cells that are responsible for bone breakdown. However, this too needs to be confirmed before it is recommended as solo therapy for the prevention or treatment of osteoporosis.
The preventive effects on many types of cancer are currently being studied in many laboratories. Interest in this area stems from epidemiological studies that show that populations which consume a diet high in soy such as they typical Asian diet, have lower incidences of breast, prostate and colon cancers. But this does not prove that the soy is the cause for this decreased risk. Many other factors are likely to be involved, but there are multiple biologically active classes of compounds found in soy that are associated with anticancer activities, including saponins, phytates, protease inhibitors, and phytosterols.
Much of the research on the effects of soy has investigated the effects of only one component at a time. However, the combined effect of the components of soy may provide additive or even synergistic effects. Therefore, the consumption of soy containing foods, such as soy milk, soy flour or tofu is likely to be more beneficial, and possibly safer than the consumption of its individual components.
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