Dietary Supplements and Functional Foods

Preface. 1 An Overview of Dietary Supplements and Functional Foods. The evolving rationale for supplement use. Adequacy and the prevention of deficiency diseases. Diet as a means to prevent chronic, age and wealth-related diseases. Supplements versus dietary change for the prevention of chronic disease. Dietary supplements and natural remedies as a safer alternative to modern medicine? Defining dietary supplements. Legal regulation of dietary supplements(the UK and EU perspective). Medicines. Non-medicinal supplements. Borderline products. Health claims. Vitamin and mineral supplements. Regulation in the USA. Supplement quality. The market for supplements. Reasons for taking supplements. To compensate for a perceived or potential inadequacy in the diet. To compensate for some perceived increase in need or defective handling of a nutrient. To treat or prevent non-deficiency diseases. To improve athletic performance. Do supplements and functional foods work? Testing their effectiveness and safety. Measures of outcome. The two main investigative approaches. The observational approach. The experimental approach. Testing: A summing up. 2 An Overview of Micronutrient Adequacy. Introduction and scope of the chapter. Judging the adequacy of micronutrient intakes. A note about American standards. Recommended daily allowances on food labels. Measuring an individual's micronutrient status using clinical or biochemical observations. Micronutrient adequacy of the UK population. Young and middle-aged adults. Children. Pregnant women. Lactating women. The elderly. Athletes in training. Summing up. 3 The Individual Vitamins. The fat-soluble vitamins. Vitamin A (retinol). Vitamin D (cholecalciferol). Vitamin E (±-tocopherol). Vitamin K (phylloquinone). The water-soluble vitamins. Vitamin B1(thiamin). Vitamin B2(riboflavin). Vitamin B3 (niacin). Vitamin B6 (pyridoxine). Vitamin B12 (cobalamins). Folic acid (folate, folacin). Biotin. Pantothenic acid. Vitamin C (ascorbic acid). 4 The Minerals. Calcium. Chromium. Copper. Fluoride. Iodine. Iron. Magnesium. Manganese. Molybdenum. Potassium. Selenium. Zinc. 5 Free Radicals and Antioxidants. Introduction. The free radical or oxidant theory of disease. Mechanisms for limiting free radical damage. Diets with plentiful supplies of (antioxidant-rich) fruits and vegetables are associated with a reduced risk of chronic diseases. What evidence is there that antioxidant supplements are beneficial or at least harmless? Antioxidants and pre-eclampsia in pregnancy. Vitamin E and dementia. Summing up the case for antioxidant supplements. 6 Natural Fats and Oils. The nature of fats, oils and other lipids. Why are we preoccupied with the balance of our dietary fats? Why are some fatty acids called 'essential'? Essential fatty acids and eicosanoid production. Fish oil supplements. What are the suggested benefits of taking fish (liver) oil supplements? Fish oil supplements and heart disease: Evidence of effectiveness. Evidence relating fish oils to inflammatory conditions such as arthritis. Fish oils, brain and behaviour. Evening primrose oil and other sources of GLA. Flaxseed oil. Conjugated linoleic acid (CLA). ²-sitosterol and the phytosterols. 7 Non-Essential 'Nutrients' that are Used as Dietary Supplements. General rationale. Glucosamine and chondroitin sulphate. Nature and functions of cartilage. Supplement forms and origins. Rationale for use and evidence of effectiveness. s-Adenosyl-methionine (SAMe). Nature and functions. Rationale for use and evidence of efficacy. Lecithin and choline. L-carnitine. Nature and synthesis of L-carnitine. Functions of carnitine. Circumstances that may increase carnitine requirements. Use of carnitine supplements. Carnitine supplements: Conclusions. Creatine. Nature and origins of body creatine. Functions of creatine. Rationale and evidence for the use of creatine supplements. Coenzyme Q10 (ubiquinone). Nature and sources of coenzyme Q10. Functions of coenzyme Q10. Rationale and evidence for the use of coenzyme Q10 supplements. Alpha(±)-lipoic acid. Nature and sources of body alpha-lipoic acid. Functions of alpha-lipoic acid. Rationale and evidence for the use of alpha-lipoic acid supplements. Methylsulphonylmethane (MSM). Nature and sources of MSM. MSM as a supplement. 8 Natural Products and Extracts. Scope of the chapter. Secondary plant metabolites. Terpenoids. Phenolic compounds (phenols and polyphenols). Nitrogen-containing alkaloids. Sulphur-containing plant secondary metabolites. How might these secondary metabolites reduce the risk of chronic disease? Natural extracts as a source of drugs. The individual plant and animal extracts. Agnus castus. Aloe vera. Bee products. Chitosan. Echinacea. Garlic. Ginger. Ginkgo biloba. Ginseng. Guarana. Kelp. Milk thistle. Saw palmetto. Spirulina and chlorella. St John's wort (Hypericum perforatum). Tea extracts. 9 Functional Foods. Introduction and scope of the chapter. A note about 'superfoods'. Phytosterols and phytostanols. Phyto-oestrogens. Probiotics, prebiotics and synbiotics. Definitions and scale of usage. The lactic acid bacteria. Breast milk and the 'bifidus factor'. What makes a good probiotic? Suggested benefits of probiotics. Effect of probiotics on incidence and severity of diarrhoea. Possible effects of probiotics on the risk of developing bowel cancer. Probiotics and the prevention of childhood eczema. Prebiotics. Synbiotics. References. Index.