Nutrient Requirements

Detrimental Effects from Excessive Intake

Jul 1, 2007 Melanie Lamprecht

Pregnant women taking dietary supplements should be cautious and aware of the potentially detrimental effects from excessive intake.

Nutritional supplements play an important role during pregnancy. The reproductive period is one in which heavy demands are made on the mother to provide the nutrients needed for the development of a normal fetus. It has been shown that during pregnancy there is an increasing need for nutrients. The increase in need for one nutrient varies from another while the need for an increase in calories is small (1).

To provide the recommended amount of protein, minerals and vitamins, a woman must select an adequate diet. In order to do so, a high-level nutritive intake for the 280 days of the normal gestation period must be maintained. This kind of responsibility subjects most pregnant women to constant pressure during a period that is known to carry a large amount of emotional stress (1).

To allow a little more freedom in the selection of food and an occasional indulgence in favourite low - nutrient food, it may be reasonable to suggest that she uses supplements that provide a balanced formula at protective levels. The Food and Nutrition Board have established dietary references to provide guidelines for adequate intakes (AI) (List 1) and tolerable upper intake levels (TUI) for certain nutrients during pregnancy (List 2) .

Nutrients Amount/Day: Non-pregnant women(19 – 50 yrs); Pregnant women

Vitamin A: 2,330 IU; 2,565 IU

Vitamin D: 200 IU; 200 IU

Vitamin E: 15 mg; 15 mg

Vitamin K: 65mg; 65mg

Vitamin C: 75 mg; 85 mg

Folate: 400 mg; 600 mg

Vitamin B6: 1.3 mg; 1.9 mg

Vitamin B12: 2.4 mg; 2.6 mg

Protein: 50 g; 60 g

Choline: 425 mg;450 mg

Calcium:1,000mg;1,000mg

Phosphorus:700; 700

Iron: 18 mg; 27 mg

Zinc: 8 mg;11 mg

Manganese:1.8 mg; 2.0 mg

Iodine:150 mg; 220 mg

Fluoride: 3 mg; 3 mg

LIST 1.Recommended Dietary Allowances and Adequate Intakes for Pregnant Women (1).

Nutrient requirements are increased by 10-100%, depending on the specific nutrient, to meet the demands of the fetus. Requirements for protein, iron, zinc, folate, ascorbic acid and B vitamins are increased during pregnancy as observed in LIST 1.

Nutrients: Tolerable Upper Intake Levels; Units/Day

Calcium: 2,500; mg

Phosphorus: 3,500; mg

Magnesium: 350; mg

Vitamin D: 2,000; IU

Vitamin A: 5000-10000; IU

Vitamin C: 2,000; mg

Vitamin B6:100; mg

Vitamin E: 1,000; mg

Iron: 45; mg

Zinc: 40; mg

Manganese: 11; mg

Selenium: 400; mg

Niacin: 35; mg

Synthetic folic acid: 1,000; µg

Choline: 3,500; mg

Iodine: 11; mg

LIST 2. Tolerable Intake Levels for Certain Nutrients During Pregnancy (1).

The main basis for caution when taking dietary supplements is the potentially detrimental effects from excessive intake. The daily total intake of these nutrients from food sources and dietary supplements should not exceed the levels shown in LIST 2 and women should be instructed to take no more than one prenatal tablet per day. A possible benefit from supplementation would be the prevention of nutrient deficiencies associated with birth defects (e.g.spina bifida and lack of folate), but harmful effects, such as toxicity of certain vitamins and minerals, are a potential risk to the pregnant woman and her fetus.

Pregnant women should be encouraged to take note of food intake as well as the use of protein powders and beverages, amino acid preparations, fortified protein bars, ergogenic aids, vitamin and mineral supplements and any supplement combinations that includes herbal compounds. Labels from all dietary supplement powders, food items and pills should be evaluated to determine whether excessive levels of specific nutrients are being consumed on a daily basis (1,2,3).

References:

1. Guthrie HA. Introductory Nutrition, 4th ed. Toronto : CV Mosby Company, 1979.

2. Polin RA, Fox WW, Abman SH. Fetal and Neonatal Physiology, 3rd ed. Saunders. 2004;2:1771-1782

3. Combs GF. The Vitamins: Fundamental Aspects in Nutrition and Health. New York. Academic Press. 1992:388-500.

## Related articles ##: Overdose of Vitamin A:Teratogenic Effects on the Fetus

## Related articles ##: Excessive Fat-Soluble Vitamins: Disruption of Normal Fetal Brain Development

The copyright of the article Nutrient Requirements in Pregnancy & Childbirth is owned by Melanie Lamprecht. Permission to republish Nutrient Requirements in print or online must be granted by the author in writing.

Nutritious requirements

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