The nutritional effects of highly unsaturated fatty acids and oleic acid are discussed. n-6 and n-3 fatty acids are necessary to maintain biological functions but cannot be synthesized in the body. Fatty acids are not only used as energy sources, but also comprise components of biological membranes, which play an important role in information transmission, as precursors of physiologically active materials such as prostaglandins, and as ligands of nuclear receptors. The cholesterol-reducing activity of linoleic acid has been known for decades. The cholesterol-reducing effect of γ-linolenic acid has been reported to be stronger than that of linoleic acid. Some studies concerning the prevention of heart diseases with α-linolenic acid have been reported. An antihypertensive effect of α-linolenic acid has been demonstrated by a large-scale study with Japanese subjects. Numerous epidemiological studies support that the intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is useful for the prevention of cardiovascular diseases. Results concerning the effectiveness of DHA for the prevention and treatment of dementia have also been reported. Research on the nutritional effects of fatty acids must still be developed.

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The deacyled phosholipid : Glycerophosphocholine (GPC), is a water-soluble compound which was found to deacylated two fatty acids from a phosphatidylcholine (PC), a kind of phospholipid. GPC or α-GPC is used in the preparation of medical supplies and functional foods as an agent which provides choline. The FDA in America has approved nutrient containing foods and dietary supplements such as choline. GPC is produced by the digestion of PC and is a absorbed by lymph vessels. The compound is partially eliminated by the portal vein. GPC is present in organisms, thus showing it to be safe and without any toxic effect. The compound is taken up by the central nervous system following peripheral administration and functions as an acetylcholine precursor to help restore memory capacity.
GPC was examined for application to the treatment of cerebrovascular disease, reduction of senile dementia (cognitive dysfunction), improvement in learning ability and promotion of non-REM sleep.

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Vitamin E is the most important and fat-soluble natural anti-oxidant. Since negative correlations between cardiovascular mortality rate and vitamin E intake have been reported, vitamin E supplement continues to be advocated. Although αa-tocopherol has been used as vitamin E, recent studies have demonstrated that γ-tocopherol and tocotrienols, the major homologues of vitamin E of the food origin, have unique health benefits. Thus, usage of γ-tocopherol, tocotrienols, or a combination of natural vitamin E homologue is emphasized, although the effects should be confirmed by large scale clinical tests. Accumulated evidence implicates vitamin K, which was originally recognized as cofactor for blood coagulation, protects against osteoporosis and atherosclerosis. Vitamin K is essential for the optimal action of the calcium-binding-proteins called osteocalcin and matrix Gla protein (MGP). Osteocalcin is essential for bone metabolism, and MGP is known to inhibit calcification in the arteries. Menaquinone-7, a major vitamin K homologue in natto, has the highest nutritional effect.

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Recent epidemiological studies on the effect of beta-carotene and/or other carotenoid (s) on cancer chemoprevention were reviewed and compared. Case-control studies and cohort studies sometimes did not provide consistent results. Studies on intake of beta-carotene and/or other carotenoid (s) and studies on their blood concentration often did not provide consistent results, either. Two major intervention studies on lung cancer in high-risk subjects indicated fed beta-carotene to possibly even enhance the risk of cancer. As a whole, beta-carotene and other carotenoids could not be unequivocally shown to qualify as agents for chemoprevention. For an epidemiological assessment of any chemoprevention potential of beta-carotene or other carotenoid (s) against cancer, the proper methods must be conducted on suitable human subjects. To do such an adequate epidemiological assessment, more detailed knowledge should be obtained beforehand by experiments.

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Dietary plant sterols and stanols reduce LDL-cholesterol concentration through inhibition of intestinal absorption of cholesterol. Their effective doses are 0.7-2 g/day. Plant sterols/stanols are solubilized in the bile salt micelle and hence, relatively decrease micellar solubility of cholesterol. This may be the major cause to inhibit cholesterol absorption. Absorption and deposition of plant sterols/stanols are low and no side-effect was observed. In some higher doses, concentrations of serum β-catotene and α-tocopherol can be reduced. However, deficiency of these vitamins has never been reported. In conclusion, plant sterols/stanols are thought to prevent atherosclerosis and to be safe dietary components.

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Naturally occurring triterpenes including triterpene saponins often exhibit a variety of biological activities such as anti-inflammatory, antitumor, chemopreventive, anti-hyperglycemic, anti-hyperlipidemic, hepatoprotective, antivirus, and antimycobacterial activities. This short review describes selected triterpenes and triterpene saponins as well as their structural modification products possessing anti-inflammatory, antitumor, and chemopreventive activities published in the literature mainly from 2002 to 2006. Some of the polyhydroxylated and carboxylated triterpenes exhibited potent biological activities in in vivo model animal experiments and these and their derivatives may have the potential of being used as anti-inflammatory, antitumor, and cancer chemopreventive agents.

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