Do lactating women need to take vitamin and mineral supplements?

August 09, 2007 by Rebecca Black

There are currently no recommendations for vitamin/mineral supplementation for lactating women but supplementation may be important, particularly for those women who choose to restrict milk intake during lactation.

In a six month prospective study of 175 exclusively breastfeeding women published in the Journal of the American College of Nutrition, dietary intake and vitamin/ mineral supplementation was compared between milk restrictors (women who consumed less than 1 cup of milk per day) and non-restrictors (women who consumed greater than 1 cup of milk per day).

Protein, calcium and vitamin D intake were found to be significantly lower in the milk restrictors. In fact, dietary intake of calcium and vitamin D was so low in the milk restrictors that their intake did not meet what is considered to be an adequate intake (AI) by the National Research Council, Food and Nutrition Board of the Institute of Medicine. Vitamin and mineral supplementation by the milk restrictors brought their calcium and vitamin D intake above AI levels; but, even with supplementation, the intake levels were still significantly lower than the women who did not restrict milk intake. In addition, estimated average requirements (EAR) for zinc, thiamin and riboflavin were not met in the milk restrictors and daily energy intake was significantly less in the milk restrictors even though there was no difference in weight loss at six months between the two groups.

Milk restriction is not recommended during lactation and where unavoidable, nutrients provided by milk should be compensated for by other foods or supplements. Nutrients provided by milk in significant amounts include calcium, vitamin D, protein, riboflavin and phosphorus.

It is recommended that lactating women consume 1000 (>18 years of age) to 1300 (<18 years of age) mg of calcium per day. Alternate sources of calcium include two groups: foods or beverages naturally high in calcium and those that have been fortified with calcium. Foods high in calcium include cheese (except cottage cheese due to loss of calcium in processing), yogurt, fish with bones (but must eat the bones which are easily crushed in canned salmon for example), green leafy vegetables such as kale, turnip greens, broccoli, and bok choy. Calcium-rich seeds, nuts, grains, and vegetables such as spinach and Swiss chard have binding factors (phytates and oxalates) and the presence of these substances can impact the absorption of calcium from food; therefore, the calcium found in dark leafy greens such as spinach will not be as bioavailable to the body (less will be absorbed than is present in food). Foods fortified with calcium include some brands of orange juice, fruit punch, soy and rice milk, calcium-fortified tofu and several specialty beverages.

Vitamin D can be obtained by exposure to the sun in individuals without liver or renal disease and is also found in fatty fish such as salmon, mackeral, and sardines and in fortified soy or cereal products.

For each cup of milk consumed an individual ingests 8 grams of protein. The Recommended Dietary Allowance for protein is 46 grams for women ages 18-50 and an additional 25 grams is required for lactating women. Thus, milk can contribute significantly to the protein intake and the protein in milk is of high biological value (HBV) thus it contains all the amino acids necessary to support growth, tissue repair and the maintenance of body functions. Special attention to assure an adequate protein intake appears to be needed for women who restrict milk during lactation. Animal products contain HBV protein and can be increased in the lactating woman's diet to meet her increased protein needs if she is a milk restrictor. Beef, pork, chicken, turkey, fish, shellfish and other edible animal products such as wild game provide HBV protein with 1 ounce providing 7 grams of protein. For the vegetarian, soy-based products are the only non-animal product with HBV protein and many soy products are also fortified with calcium and vitamin D as well. Complimentary protein mixing (rice and beans, nuts/ seeds combined with grains etc.) is another way the vegetarian can meet protein needs.

Milk is a primary source of riboflavin; however, cereals and grains are enriched with riboflavin and if included in a daily diet can help one meet the need for riboflavin.

Phosphorus is abundant in the food supply with high amounts in foods that contain protein. Milk, meats, eggs, peanut butter, and legumes, nuts and seeds are naturally high in phosphorus. Carbonated beverages are also high in phosphorus (phosphoric acid is an additive) but are not recommended as a source of phosphorus due to being linked to decreases in bone density (believed to be due to the milk-displacement effect of drinking sodas instead of milk).

For the woman unable to increase the above foods to meet needs, vitamin/ mineral supplements may be in order. It is important to remember that calcium can be found in several forms (gluconate, citrate, malate, carbonate etc) so when purchasing a supplement look for the amount of elemental calcium available and choose a supplement with vitamin D (vitamin D is needed for calcium absorption). Additionally, the body cannot absorb more than about 500 mg of elemental calcium at a time and as the amount of calcium in a meal or supplement goes up, the percentage that is absorbed goes down. Calcium supplements should not be taken at the same time as other supplements due to interference with absorption.

Mannion CA ; Gray-Donald K ; Johnson-Down L ; Koski KG .Lactating women restricting milk are low on select nutrients. J Am Coll Nutr. 2007; 26(2):149-55.

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