One size rarely fits all! - nutrition and metabolism during pregnancy

Better Nutrition, July, 1999 by Tamra B. Orr

Upping your energy during pregnancy what works for you & baby.

Women have known for decades that one-size-fits-all is a fallacy, and now a new study in the American Journal of Clinical Nutrition indicates that researchers suspect pregnant women's nutritional needs are not a generic, one-size-fits-all concept, either. The study followed healthy women from pre-conception through post-partum to see how they met the energy demands of pregnancy, and if current dietary recommendations typically given out during prenatal care were sufficient.

Up the energy!

A pregnant woman undeniably needs more energy for the growth of the fetus, placenta, uterus, and breasts, as well as for fat storage and for her metabolism to maintain all these new tissues. Thirty years ago, experts decided a woman needed an extra 250 to 300 calories a day to support all this growth. Recently, the National Academy of Sciences changed these recommendations to 150 calories in the first trimester and 350 in the second and third. Elizabeth Somer, M.A., R.D., author of Nutrition for a Healthy Pregnancy says that the key is not how much you gain as how you gain it. Weight gain in pregnancy should be a gradual process, she states. No spikes in the scale reading, but an even, steady gain, with minimal gain in the first trimester and a half a pound to a pound a week in the second and third trimesters.

Researchers Kopp-Hoolihan, et al., demonstrated that pregnant women's metabolisms vary far more than was thought, and that each woman seems to have her own way of handling the increased energy needs, depending on her body size, levels of physical activity, and how efficiently she converts food into fuel. Somer agrees. A young, pregnant, overly skinny woman's caloric needs will differ greatly from a 40-year-old obese woman's.

For example, a marathon runner with only 10 percent body fat will gain differently than a woman with 25 percent body fat. For the woman with ideal body weight, a weight gain of 25 to 35 pounds is usually recommended. Less than a 20- pound gain increases the chance of a low-birth-weight baby and the host of health problems that goes with that. Gaining more than 40 pounds won't make a bigger, healthier baby, it'll just make losing the weight that much harder. Losing the pregnancy weight is often a concern for women, but as Somer reminds new mothers, it took almost a year to gain that weight; plan on it taking about a year to take it back off again.

Keepin' in mind ...

Somer and many other researchers emphasize, however, that mineral and vitamin needs in pregnancy, with a few exceptions, stay rather consistent, regardless of other factors. Pregnancy doubles a woman's need for folic acid and a deficiency can result in anemia for mother and neural defects for baby. Women are often able to meet the need for folic acid through foods like leafy, green vegetables, some fruits and organ meats, but others need supplements. Iron is another mineral needed in larger amounts, especially in the later stages of pregnancy; but it is much more difficult to obtain through diet, so supplements are frequently recommended.

How can a woman know she is getting the right advice when she goes in for prenatal care? The reality is, says Somer, the amount of nutritional counseling you get from your physician can be embarrassingly low and you can't always depend on him or her for the best advice. As Kopp-Hoolihan, et al., have shown in their research, every woman's metabolism seems to have its own way of adjusting to the physical demands of pregnancy and doctors may be best advised to simply watch weight gain patterns and only make recommendations when a deviation is seen from the normal gradual pattern.

In fact, Roy Pitkin, researcher at the University of California states in his editorial for the American Journal of Clinical Nutrition something that many women have suspected for a long time: Mother Nature is a pretty good obstetrician.

REFERENCES

http://www.4woman.org/faq/preg-diet.htm

Kopp-Hoolihan, Lori, et al. "Longitudinal assessment of energy balance in well-nourished, pregnant women," American Journal of Clinical Nutrition 69:697-704, 1999.

Pitkin, Roy M. "Energy in pregnancy," American Journal of Clinical Nutrition 69:583, 1999.

Somer, Elizabeth, R.D., M.A. Personal interview. May 6, 1999.

Tamra Orr has been a professional freelance writer for almost 20 years in the areas of health, nutrition, and child development. Tami lives in Warsaw, Indiana, with her four children and her husband, a chiropractor at the Orr-Barker Chiropractic Center.