Folate and Folic Acid

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim (Chapter 4)

Role of folate and folic acid in human metabolic processes

General Considerations of B-complex Vitamins

Reference from the joint venture of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim. (Chapter 3)

General considerations for B-complex vitamins

Notes on suggested recommendations

6. Food and Nutrition Board, Institute of Medicine/National Academy of Sciences-National Research Council. 1998. Dietary Reference Intake: Folate, Other B Vitamins, and Choline. Washington, D.C., National Academy Press.

Thiamin, Riboflavin, Niacin, Vitamin B6, Pantothenic Acid and Biotin...continued #6.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim. (Chapter 3)

Biotin

Background with requisite function in human metabolic processes

Thiamin, Riboflavin, Niacin, Vitamin B6, Pantothenic Acid and Biotin...continued #5.

Reference from the joint report of FAO/WHO expert consultation of Human Vitamins and Minerals verbatim. (Chapter 3)

Pantothenate

Background with requisite function in human metabolic processes

Deficiency

8. McCormick, D.B. 1997. Vitamin, Structure and Function of. In: Encyclopedia of Molecular Biology and Molecular Medicine, Vol. 6. Meyers, R.A., ed. Weinheim: VCH, p. 244-52.

9. McCormick, D.B & Greene, H.L. 1994. Vitamins. In: Tietz Textbook of Clin Chem., 2nd edition. Burtis, V.A., Ashwood, E.R., eds. Philadelphia: W.B. Saunders, p. 1275-1316.

100. McCormick, D.B. 1988. Pantothenic Acid. In: Modern Nutrition in Health and Disease, 6th edition. p.383-7. Shils, M.E., Young, V.R., eds. Philadelphia: Lea & Febiger.

101. Plesofsky-Vig, N. 1994. Pantothenic acid and co-enzyme A. In: Modern Nutrition in Health and Disease, 8th edition. Shils, M.E., Olson, J.A., Shike, M., eds. Philadelphia, Lea

& Febiger, p. 395-401.

The widespread occurrence of releasable pantothenic acid in food makes a dietary deficiency unlikely (8, 9, 100, 101). If a deficiency occurs, it is usually accompanied by deficits of other nutrients. 

Thiamin, Riboflavin, Niacin, Vitamin B6, Pantothenic Acid and Biotin...continued #4.

Reference from the joint report of FAO/WHO expert consultation of Human Vitamins and Minerals verbatim. (Chapter 3)

Vitamin B6

Background with requisite function in human metabolic processes

Deficiency

72. McCormick, D.B. 1988. Vitamin B6. In: Modern Nutrition in Health and Disease, 6th edition. Shils, M.E., Young, V.R., eds. Philadelphia: Lea & Febiger, p. 376-82.

A deficiency of vitamin B6 alone is uncommon because it usually occurs in association with a deficit in other B-complex vitamins (72). Early biochemical changes include decreased levels of plasma PLP and urinary 4-pyridoxic acid. These are followed by decreases in synthesis of transaminases (aminotransferases) and other enzymes of amino acid metabolism such that there is an increased urinary xanthurenate and a decreased glutamate conversion to the antineurotransmitter γ-aminobutyrate.

Thiamin, Riboflavin, Niacin, Vitamin B6, Pantothenic Acid and Biotin...continued #3.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim. (Chapter 3)

Niacin

Background with requisite function in human metabolic processes

Deficiency

8. McCormick, D.B. 1997. Vitamin, Structure and Function of. In: Encyclopedia of Molecular Biology and Molecular Medicine, Vol. 6. Meyers, R.A., ed. Weinheim: VCH, p. 244-52.

9. McCormick, D.B & Greene, H.L. 1994. Vitamins. In: Tietz Textbook of Clin Chem., 2nd edition. Burtis, V.A., Ashwood, E.R., eds. Philadelphia: W.B. Saunders, p. 1275-1316.

61. McCormick, D.B. 1988. Niacin. In: Modern Nutrition in Health and Disease, 6th edition. Shils, M.E., Young, V.R., eds. Philadelphia: Lea & Febiger, 370-5.

Niacin (nicotinic acid) deficiency classically results in pellagra, which is a chronic wasting disease associated with a characteristic erythematous dermatitis that is bilateral an symmetrical, a dementia after mental changes including insomnia and apathy preceding an overt encephalopathy, and diarrhoea resulting from inflammation of the intestinal mucous surfaces (8, 9, 61).

How to Accomplish Dietary Diversity in Practice

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim. (Chapter 2)

4. FAO/ILSI. 1997. Preventing Micronutrient Malnutrition: A Guide to Food-Based Approaches, ILSI Press, Washington DC. 

It is essential to work on strategies, which promote and facilitate dietary diversification to achieve complementarity of cereal or tuber-based diets with foods rich in micronutrients in populations with limited economics or limited access to food. A recent FAO and International Life Sciences Institute (4) publication proposed strategies to promote dietary diversification within the implementation of food-based approaches. 

These strategies, which follow, have been adapted or modified based on the discussions held in this consultation:

Food-based approaches to meeting vitamin and mineral needs - Iron and Zinc

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim. (Chapter 2)

Minerals such as iron and zinc are low in cereal and tuber-based diets, but the addition of legumes can slightly improve the iron content of those diets. However, the bio-availability of this non-heme iron source is low.

Therefore, it is not possible to meet the recommended levels of iron and zinc in the staple-based diets through a food-based approach unless some meat, poultry, or fish is included. For example adding a small portion (50 g) of meat, poultry, or fish will increase the total iron content as well as the amount of bio-available iron.

Food-based Approaches to Meeting Vitamin and Mineral Needs...continued #2.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim. (Chapter 2)

The recent interest in the role of phyto-chemicals and antioxidants on health and their presence in plant foods lend further support to the recommendation for increasing vegetables and fruit consumed in the diet. The need for dietary diversification is supported by the knowledge of the interrelationships of food components, which may enhance the nutritional value of foods and prevent undesirable imbalances, which may limit the utilisation of some nutrients.

For example, fruits rich in ascorbic acid will enhance the absorption of ionic iron. If energy intake is low (<8.368 MJ/day), for example, in the case of young children, sedentary women, or the elderly, the diet may not provide vitamin and mineral intakes sufficient to meet the RNIs. This situation may be of special relevance to the elderly, who are inactive, have decreased lean body mass, and typically decrease their energy intake. Young children, pregnant women, and lactating women, who have greater micronutrient needs relative to their energy needs, will also require increased micronutrient density. 

Food-based Approaches to Meeting Vitamin and Mineral Needs...continued #1.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim. (Chapter 2)

Food-based Approaches to Meeting Vitamin and Mineral Needs

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim. (Chapter 2)

Dietary patterns have varied over time depending on the agricultural practices and the climatic, ecologic, cultural, and socio-economic factors, which determine available foods. At present, virtually all dietary patterns adequately satisfy or even exceed the

nutritional needs of population groups. This is true except where socio-economic conditions limit the capacity to produce and purchase food or aberrant cultural practices restrict the choice of foods.

It is thought that if people have access to a sufficient quantity and variety of foods, they will meet their nutritional needs. The current practice of evaluating nutritive value of diets should include not only energy and protein adequacy but also the micronutrient density of the diet.  

Introduction of Human Vitamins and Minerals...continued #4.

Reference from the joint report of FAO/WHO expert consulation on Human Vitamins and Minerals verbatim. (Chapter 1)

Dr Nath reminded the participants that they had been invited to the Consultation as independent experts and that their participation in the Consultation was to be in their individual capacity and not as a representative of any organization, affiliation, or government. He underscored the importance of drawing conclusions and making recommendations based on science, which is traceable to studies conducted largely in humans. 

Introduction of Human Vitamins and Minerals...continued #3.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim. (Chapter 1)

Upper tolerable nutrient intake level

Upper tolerable nutrient intake levels (ULs) have been defined for some nutrients. ULs are the maximum intake from food that is unlikely to pose risk of adverse health effects from excess in almost all (97.5 percent) apparently healthy individuals in an age and sex-specific population group. ULs should be based on long-term exposure from food, including fortified food products.

2. Anonymous. 1997. A Model for the Development of Tolerable Upper Intake Levels. Nutr. Revs., 55: 342-351.

Introduction of Human Vitamins and Minerals...continued #2.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim. (Chapter 1)

The relevance of the biological effects starts with the most extreme case, that is, the prevention of death. For nutrients where sufficient data on mortality are not available, the nutrient intake that prevents clinical disease or sub-clinical pathological conditions, identified by biochemical or functional assays, is used.

The next sets of biomarkers that are used to define requirements include measures of nutrient stores or critical tissue pools. Intakes to assure replete body stores are important when deficiency conditions are highly prevalent. Presently, approaches to define requirements of most nutrients use several criteria examined in combination, functional assays of sub-clinical conditions are considered the most relevant.

Introduction of Human Vitamins and Minerals...continued #1.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim. (Chapter 1)

Terms of reference and process

The terms of reference for the Expert Panel were the following:

􀂃 To review the full scope of vitamin and minerals requirements, including their role in normal human physiology and metabolism and in deficiency disease conditions. To focus on the requirements of the essential vitamins and minerals, including vitamins A, C, D, E, and K; the B vitamins; calcium; iron; magnesium; zinc; selenium; and iodine. 

Introduction of Human Vitamins and Minerals

Before I proceed, please allow me to say some words to all of you, my readers. 

At first, I thought the introduction of this joint report of FAO/WHO is not really important. However, when I finished the last chapter (chapter 17) I scrolled to the top and read again the Introduction. I realized this is a must read to the readers because this was how, and why the FAO/WHO came up to organize this expert consultation in making their reports. 

This book is an eye opener to those, like me, who wants to know the real functions of vitamins and minerals. Like I said in my previous post, this is the answer to my questions about vitamins and minerals, and now I can say, I finally found it. I need to read this over and over again, because 17 chapters of the book is not that easy to remember everything in one to three readings. 

Dietary Antioxidants: A Consideration of Factors Influencing Requirements...continued #4.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim. (Chapter 17)

A requirement for antioxidant nutrients

36. Halliwell, B., Gutteridge, J.M.C. & Cross, C.E. 1992. Free radicals, antioxidants, and

Human disease: where are we now? J. Lab. Clin. Med., 119: 598-620.

Free radicals are a product of tissue metabolism, and the potential damage which they can cause is minimised by the antioxidant capacity and repair mechanisms within the cell. Thus in a metabolically active tissue cell in a healthy subject with an adequate dietary intake, damage to tissue will be minimal and most of the damage occurring will be repaired (36).

15. Hennekens, C.H. 1986. Micronutrients and cancer prevention. N. Engl. J. Med., 315:1288-1289.

16. Van Poppel, G., Kardinaal, A.F.M., Princen, H.M.G. & Kok, F.J. 1994. Antioxidants and coronary heart disease. Ann. Med., 26:429-434.

89. Colditz, G.A., Branch, L.G. & Lipnick, R.J. 1985. Increased green and yellow vegetable intake and lowered cancer deaths in an elderly population. Am. J. Clin. Nutr., 41: 32-36.

Dietary Antioxidants: A Consideration of Factors Influencing Requirements...continued #3.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

Vitamin C

51. Myllyla, R., Kuutti-Savolainen, E. & Kivirikko, K.I. 1978. The role of ascorbate in the prolyl hydroxylase reaction. Biochem. Biophys. Res. Comm., 83: 441-448.

52. Hulse, J.D., Ellis, S.R. & Henderson, L.M. 1978. β-Hydroxylation of trimethyllysine by an α-ketoglutarate-dependent mitochondrial dioxygenase. J. Biol. Chem., 253:1654-1659.

53. Bates, C.J. 1981. The function and metabolism of vitamin C in man. In: Counsell JN, Hornig DH, eds. Vitamin C - ascorbic acid. p.1-22. London: Applied Science Publishers.

54. Zannoni, V.G. & Lynch, M.M. 1973. The role of ascorbic acid in drug metabolism. Drug Metab. Rev., 2: 57-69.

Dietary Antioxidants: A Consideration of Factors Influencing Requirements...continued #2.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

Nutrients with radical-quenching properties

Vitamins C and E are the principal nutrients which possess radical-quenching properties. Both are powerful antioxidants, and the most important difference between these two compounds stems from their different solubility in biologic fluids. Vitamin C is water soluble and is therefore especially found in the aqueous fractions of the cell and in body fluids whereas vitamin E is highly lipophilic and is found in membranes and lipoproteins.

Dietary Antioxidants: A Consideration of Factors Influencing Requirements...continued #1.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

3. Thurnham, D,I. 1990. Antioxidants and pro-oxidants in malnourished populations. Proc. Nutr. Soc., 48: 247-259.

29. Thurnham, D.I. 1994. β-Carotene, are we misreading the signals in risk groups? Some analogies with vitamin C. Proc. Nutr. Soc., 53:557-569.

30. Thurnham, D.I. 1997. Impact of disease on markers of micronutrient status. Proc. Nutr. Soc., 56: 421-431.

Pro-oxidant activity of biologic antioxidants

Most biologic antioxidants are antioxidants because when they accept an unpaired electron, the free radical intermediate formed has a relatively long half-life in the normal biologic environment. The long half-life means that these intermediates remain stable for long enough to interact in a controlled fashion with intermediates which prevent autoxidation, and the excess energy of the surplus electron is dissipated without damage to the tissues.

Dietary Antioxidants: A Consideration of Factors Influencing Requirements

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

28. Koj., A. 1985. Biological functions of acute phase proteins. In: Gordon AH, Koj A, eds. The acute phase response to injury and infection. p.145-160. London: Elsevier.

3. Thurnham, D,I. 1990. Antioxidants and pro-oxidants in malnourished populations. Proc. Nutr. Soc., 48: 247-259.

29. Thurnham, D.I. 1994. β-Carotene, are we misreading the signals in risk groups? Some analogies with vitamin C. Proc. Nutr. Soc., 53:557-569.

30. Thurnham, D.I. 1997. Impact of disease on markers of micronutrient status. Proc. Nutr. Soc., 56: 421-431.

Adequacy of Zinc Intakes in Relation to Requirement Estimates

Reference from the joint report of FAO/WHO expert consultation of Human Vitamins and Minerals verbatim.

32. AO/IAEA/WHO. 1996. Trace elements in Human nutrition and health. Geneva, World Health Organization.

43. Gibson, R.S. & Ferguson, E.L. 1998. Assessment of dietary zinc in a population. Am. J. Clin. Nutr., 68(suppl.): 430S-434S

The risk for inadequate zinc intakes in children has been evaluated by using the suggested estimates of zinc requirements (32) and by using data available on food composition and dietary intake in different parts of the world (43).

Upper Limits of Zinc Intake

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

Only a few occurrences of acute zinc poisoning have been reported. The toxicity signs are nausea, vomiting, diarrhoea, fever, and lethargy and have been observed after ingestion of 4-8 g (60-120 mmol) zinc. Long-term zinc intakes higher than the requirements could, however, interact with the metabolism of other trace elements. Copper seems to be especially sensitive to high zinc doses.

Inter-individual Variations in Zinc Requirements and Recommended Nutrient Intakes

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

Zinc Requirements

Reference from the joint report of FAO/WHO expert consultation on Human Vitamin and Minerals verbatim.

Populations at Risk for Zinc Deficiency

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

32. AO/IAEA/WHO. 1996. Trace elements in Human nutrition and health. Geneva, World

Health Organization.

29. Simmer, K., Khanum, S., Carlsson, L. & Thompson, R.P.H. 1988. Nutritional rehabilitation in Bangladesh – the importance of zinc. Am. J. Clin. Nutr., 47: 1036-40.

13. Brown, K., Peerson, J.M. & Allen, L.H. 1998. Effects of zinc supplementation on children’s growth. In: Role of trace elements for health promotion and disease prevention. Sandström, B., Walter, P., eds. Bibliotheca Nutritio et Dieta, Basel: Karger; 54: 76-83.

Dietary Sources and Availability of Zinc

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

19. Sian, L., Mingyan, X., Miller, L.V., Tong, L., Krebs, N.F. & Hambidge, K.M. 1996. Zinc absorption and intestinal losses of endogenous zinc in young Chinese women with marginal zinc intakes. Am. J. Clin. Nutr., 63: 348-53.

23. Knudsen, E., Jensen, M., Solgaard, P., Sørensen, S.S. & Sandström, B. 1995. Zinc absorption estimated by fecal monitoring of zinc stable isotopes validated by comparison with whole-body retention of zinc radioisotopes in Humans. J. Nutr., 125: 1274-1282.

25. Hunt, J.R., Gallagher, S.K., Johnson, L.K. & Lykken, G.I. 1995. High- versus low-meat diets: effects on zinc absorption, iron status, and calcium, copper, iron, magnesium, manganese, nitrogen, phosphorus, and zinc balance in postmenopausal women. Am. J. Clin. Nutr., 62: 621-32.

32. AO/IAEA/WHO. 1996. Trace elements in Human nutrition and health. Geneva, World

Health Organization.

20. Sandström, B. 1989. Dietary pattern and zinc supply. In: Zinc in Human biology. Mills C.F. ed. p. 350-363. Devon , U.K., Springer-Verlag.

Zinc Metabolism and Homeostasis

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

3. Sandström, B. 1997. Bio-availability of zinc. Eur. J. Clin. Nutr., 51(suppl. 1): S17-S19

Zinc absorption is concentration dependent and occurs throughout the small intestine. Under normal physiologic conditions, transport processes of uptake are not saturated. Zinc administered in aqueous solutions to fasting subjects is absorbed efficiently (60–70 percent), whereas absorption from solid diets is less efficient and varies depending on zinc content and diet composition (3).

Role of Zinc in Human Metabolic Processes

Reference from the joint report of FAO/WHO expert consultation on Human Vitamin and Minerals verbatim. 

Zinc is present in all body tissues and fluids. The total body zinc content has been estimated to be 30 mmol (2 g). Skeletal muscle accounts for approximately 60 percent of the total body content and bone mass, with a zinc concentration of 1.5–3 μmol/g (100-200 μg/g), for approximately 30 percent.

Upper Tolerable Nutrient Level for Selenium

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

80. WHO. 1987. Selenium, Geneva, World Health Organization. (Environmental Health Criteria, 58).

A comprehensive account of the clinically significant biochemical manifestations of chronic and acute intoxication from selenium arising from high concentrations in food, drinking water, and the environment were published jointly by WHO and the United Nations Environment Programme and the International Labour Organisation (80).

Selenium Requirements During Pregnancy and Lactation

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

90. Scientific Committee for Food. 1993. Nutrient and Energy Intakes for the European Community. Report of the Scientific Committee for Food, Thirty First Series. Office for Official Publications of the European Communities, Brussels.

91. Department of Health. 1991. Dietary Reference Values for Food Energy and Nutrient Intakes for the United Kingdom. Report on Health and Social Subjects No.41. London, HMSO.

92. Netherlands Food and Nutrition Council. 1989. Recommended Dietary Allowances. The Netherlands. The Hague.

Recommended Selenium Intakes

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

87. National Research Council, Food and Nutirtion Board. 1988. Recommended Dietary Allowances, 10 edition. Washington, D.C. US National Academy Press.

18. Yang, G-Q., Zhu, L-Z., Liu, S-J., Gu, L-Z., Qian, P-C., Huang, J-H. & Lu, M-D. 1984. Human selenium requirements in China. In: Selenium in Biology and Medicine. Combs, G.R., Spallholz, J.E., Levander, O.A., Oldfield, J.E. eds. p.589-607. New York, AVI Van Nostrand.

Because balance techniques were shown to be inappropriate for determining selenium requirements, the WHO-FAO-IAEA report (86) presented requirement estimates based on of epidemiologic evidence derived from areas of China endemic or non-endemic for Keshan disease (18).

Criteria for Assessing Selenium Requirements

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

84. Levander, O.A. 1988. The global selenium agenda. In: Trace Elements in man and animals - 6. Proceeding of the 6th International Symposium on Trace Elements in Man

and Animals. Hurley, L.S., Keen, C.L., Lonnerdal, B., Rucker, R.B. eds. New York Plenum Press Inc.

Absorption and Bio-availability

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

80. WHO. 1987. Selenium, Geneva, World Health Organization. (Environmental Health Criteria, 58).

81. Patterson, B.H., Zech, L.A., Swanson, C.A. & Levander, O.A. 1993. Kinetic modelling of selenium in Humans using stable isotope tracers. J. Trace Elem. Electrolyte Health Dis. 7: 117-120.

Selenium compounds are generally very efficiently absorbed by humans, and selenium absorption does not appear to be under homeostatic control (80). For example, absorption of the selenite form of selenium is greater than 80 percent whereas that of selenium as selenomethionine or as selenate may be greater than 90 percent (80, 81).

The Influence of Diet on Selenium Status

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

43. Mahalingam, T.R., Vijayalakshni, S., Krishna, & Prabhu, R. 1997. Studies on some trace and minor elements in blood. A survey of the Kalpakkan (India) population. Part III: Studies on dietary intake and its correlation to blood levels. Biol. Trace Elem. Res., 57: 223-238.

44. Levander, O.A. 1987. A global view of human selenium nutrition. Annu. Rev. Nutr., 7:227-250.

8. Reilly, C. 1996. Selenium in food and health. London, Blackie Academic and

Professional.

18. Yang, G-Q., Zhu, L-Z., Liu, S-J., Gu, L-Z., Qian, P-C., Huang, J-H. & Lu, M-D. 1984. Human selenium requirements in China. In: Selenium in Biology and Medicine. Combs, G.R., Spallholz, J.E., Levander, O.A., Oldfield, J.E. eds. p.589-607. New York, AVI Van Nostrand.

43. Mahalingam, T.R., Vijayalakshni, S., Krishna, & Prabhu, R. 1997. Studies on some trace and minor elements in blood. A survey of the Kalpakkan (India) population. Part III: Studies on dietary intake and its correlation to blood levels. Biol. Trace Elem. Res., 57: 223-238.

45. Varo, P. & Koivistoinen, P. 1980. Mineral element composition of Finnish foods. XII General discussion and nutritional evaluation. Acta Agric. Scand., Supplement No. 22;165-171.

46. MAFF. 1997. UK Dietary Intake of Selenium. MAFF Food Surveillance Information Sheet: No. 126. London, MAFF/HMSO.

Selenium Deficiency...continued.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamin and Minerals verbatim.

Selenium and thyroid hormones

35. Arthur, J.R., Nicol, F. & Beckett, G.J. 1993. Selenium deficiency thyroid hormone metabolism and thyroid hormone deiodinases. Am. J. Clin. Nutr., Supplement, 57:

236S-239S.

36. Corrilain, B., Contempre, B., Longombe, A.O., Goyens, P., Gervy-Decoster, C., Lamy, F., Vanderpas, J.B. & Dumont, J.E. 1993. Selenium and the thyroid: how the relationship was established. Am. J. Clin. Nutr., Supplement 57: 244S-248S.

The importance of selenium for thyroid hormone metabolism (35, 36) is evident from changes in the T3-T4 ratio which develop after relatively mild selenium depletion in infants and elderly (65+ years) subjects.

Selenium Deficiency...continued.

Reference from the joint report of FAO/WHO expert consultation of Human Vitamins and Minerals verbatim.

Selenium status and susceptibility to infection

17. Levander, O.A. & Beck, M.A. 1997. Interacting nutritional and infectious ecologies of Keshan Disease. Biol. Trace Elem. Res., 56: 5-21.

As stated earlier, the expressions of the cardiac lesions of Keshan disease probably involve not only the development of selenium deficiency but also the presence of a Coxsackie virus (BA) infection. Animal studies have confirmed that selenium-deficient mice infected with Coxsackie virus (CVB/0) were particularly susceptible to the virus. These studies also illustrated that passage of the virus through selenium-deficient subjects enhanced its virulence (17).

Selenium Deficiency

Reference from the joint report of FAO/WHO expert consultation of Human Vitamins and Minerals verbatim.

Non-endemic deficiencies of selenium

10. Brennan, M.F. & Horwitz, G.D. 1984. Total parenteral nutrition in surgical patients. Advances in Surgery, 17: 1-7.

11. van RiJ., A.M., Thompson, D., McKenzie, J.M. & Robinson, M.F. 1979. Selenium deficiency in total parenteral nutrition. Am. J. Clin. Nutr., 32: 2076-2085. 

Biochemical evidence of selenium depletion (e.g., a decline in blood GSHPx activity) is not uncommon in subjects maintained on parenteral or enteral feeding for long periods. Blood selenium values declining to one-tenth of normal values have been reported when the selenium content of such preparations has not been maintained by fortification (10, 11).

The Role of Selenium in Human Metabolic Processes

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

1. Levander, O.A. 1986. Selenium. In: Trace elements in human and animal nutrition 5th edn. Mertz, W. ed. p 209-279. Orlando, Florida 209-279. Academic Press Inc. 

2. Arthur, J.R. & Beckett, G.J. 1994. Neometabolic roles for selenium. Proc. Nutr. Soc. 53: 615-624.

3. Ge, K. & Yang, G. 1993. The epidemiology of selenium deficiency in the etiological study of endemic diseases in China. Am. J. Clin. Nutr., Supplement 57: 259S-263S.

Upper Tolerable Limits of Magnesium Intake

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

63. Food and Nutrition Board, Institute of Medicine. 1997. Dietary reference intakes for Calcium, Phosphorous, Magnesium, Vitamin D, and Flouride. Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. Washington D.C., National Academy Press.

Derivation of Allowances for Magnesium...continued.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

The detailed studies of magnesium economy during malnutrition and subsequent therapy, with or without magnesium supplementation, provide reasonable grounds that the dietary magnesium recommendations derived herein for young children are realistic. Data for other ages are more scarce and are confined to magnesium balance studies. Some have paid little attention to the influence of variations in dietary magnesium content and of the effects of growth rate before and after puberty on the normality of magnesium-dependent functions.