Author

Siew Sun Wong

Date of Award:

1999

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Nutrition, Dietetics, and Food Sciences

Department name when degree awarded

Nutrition and food Sciences

Advisor/Chair:

Ronald G. Munger

Abstract

Recently maternal intake of multivitamins has been associated with a reduced risk of orofacial clefts (OFC)in human epidemiologic studies. In the Philippines, vitamin B-6 deficiency was found to be associated with increased risk of OFCs. The birth prevalence of OFCs in the Philippines is among the highest known, but Filipino emigrants in the United States have lower rates, indicating that environmental factors may play an important role in causing OFCs in the Philippines.

The prevalence and possible causes of vitamin B-6 deficiency were investigated through dietary and biochemical assessments in case-control study in Negros Occidental, Philippines. Mothers with OFC offspring (cases) were ascertained during a 2-week OFC surgical mission of Operation Smile in 1997, and mothers without OFC offspring (controls) were recruited at randomly selected neighborhood health centers.

Sixty-three percent case-mothers and 41 percent control-mothers were vitamin B-6-deficient. Dietary vitamin B-6 intake was low in both cases and controls but lower in cases. Case-mothers consumed 9.4 percent fewer calories than the control-mothers. Rice was the major contribution of total energy, carbohydrate, and protein for both cases and controls. Both cases and controls consumed fruits, seafood, dairy, fats, and oils with similar frequency, but cases consumed grains and grain products, vegetables, meats, beans and bean products, and roots less frequently. The vitamin B-6 activity coefficient, an indicator of vitamin B-6 deficiency, was correlated positively with plasma homocystine and negatively with plasma and red cell folate in cases only. No significant correlations were found between vitamin B-6 status and maternal age, smoking, or drinking, in either cases or controls.

Vitamin B-6 deficiency appears to be an important yet complex problem in Negros Occidental because it is widespread and strongly associated with the risk of OFC birth defects. This condition may be a consequence of 1) high polished rice consumption, 2) low vitamin B-6 intake from other food sources, 3) presence of glycosylated vitamin B-6 in plant foods, 4) high vitamin C-induced vitamin B-6 hydroxylation, or 5) a potential zinc deficiency.

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