Food and Agricultural Organization of the United Nations PA N I S F I A T G u id e in e s o n fo o d fo r tific atio n w th m ic r o n u tr ie n ts Interest in micronutrient malnutrition has increased greatly over the last few years. One of the main reasons is the realization that micronutrient malnutrition contributes substantially to the global burden of disease. Furthermore, although micronutrient malnutrition is more frequent and severe in the developing world and among disadvantaged populations, it also represents a public health problem in some industrialized countries. Measures to correct micronutrient deficiencies aim at ensuring consumption of a balanced diet that is adequate in every nutrient. Unfortunately, this is far from being achieved everywhere since it requires universal access to adequate food and appropriate dietary habits. Food fortification has the dual advantage of being able to deliver nutrients to large segments of the population without requiring radical changes in food consumption patterns.

Guidelines on food fortification with micronutrients

We studied the relation of serum vitamin A (retinol), beta-carotene, vitamin E, and selenium to the risk of lung cancer, using serum that had been collected during a large blood-collection study performed in Washington County, Maryland, in 1974. Levels of the nutrients in serum samples from 99 persons who were subsequently found to have lung cancer (in 1975 to 1983) were compared with levels in 196 controls who were matched for age, sex, race, month of blood donation, and smoking history. A strong inverse association between serum beta-carotene and the risk of squamous-cell carcinoma of the lung was observed (relative odds, 4.30; 95 percent confidence limits, 1.38 and 13.41). Mean (+/- SD) levels of vitamin E were lower among the cases than the controls (10.5 +/- 3.2 vs. 11.9 +/- 4.90 mg per liter), when all histologic types of cancer were considered together. In addition, a linear trend in risk was found (P = 0.04), so that persons with serum levels of vitamin E in the lowest quintile had a 2.5 times higher risk of lung cancer than persons with levels in the highest quintile. These data support an association between low levels of serum vitamin E and the risk of any type of lung cancer and between low levels of serum beta-carotene and the risk of squamous-cell carcinoma of the lung.

Serum beta-carotene, vitamins A and E, selenium, and the risk of lung cancer.

Methods for assessing nutritional status of patients with renal failure.

Effect of food fortification on folic acid intake in the United States

Pyridoxal phosphate is the cofactor for over 100 enzyme-catalysed reactions in the body, including many involved in the synthesis or catabolism of neurotransmitters. Inadequate levels of pyridoxal phosphate in the brain cause neurological dysfunction, particularly epilepsy. There are several different mechanisms that lead to an increased requirement for pyridoxine and/or pyridoxal phosphate. These include: (i) inborn errors affecting the pathways of B(6) vitamer metabolism; (ii) inborn errors that lead to accumulation of small molecules that react with pyridoxal phosphate and inactivate it; (iii) drugs that react with pyridoxal phosphate; (iv) coeliac disease, which is thought to lead to malabsorption of B(6) vitamers; (v) renal dialysis, which leads to increased losses of B(6) vitamers from the circulation; (vi) drugs that affect the metabolism of B(6) vitamers; and (vii) inborn errors affecting specific pyridoxal phosphate-dependent enzymes. The last show a very variable degree of pyridoxine responsiveness, from 90% in X-linked sideroblastic anaemia (delta-aminolevulinate synthase deficiency) through 50% in homocystinuria (cystathionine beta-synthase deficiency) to 5% in ornithinaemia with gyrate atrophy (ornithine delta-aminotransferase deficiency). The possible role of pyridoxal phosphate as a chaperone during folding of nascent enzymes is discussed. High-dose pyridoxine or pyridoxal phosphate may have deleterious side-effects (particularly peripheral neuropathy with pyridoxine) and this must be considered in treatment regimes. None the less, in some patients, particularly infants with intractable epilepsy, treatment with pyridoxine or pyridoxal phosphate can be life-saving, and in other infants with inborn errors of metabolism B(6) treatment can be extremely beneficial.

B6-responsive disorders: a model of vitamin dependency.

(1973). Laboratory Tests for the Assessment of Nutritional Status. CRC Critical Reviews in Clinical Laboratory Sciences: Vol. 4, No. 3, pp. 215-340.

James H. Skala

Papers

Laboratory Tests for the Assessment of Nutritional Status