Pregnancy Nutrition Concerns
The terms organic and natural are sometimes placed on food packaging. In some areas, these terms have specific definitions. For example, the US Food and Drug Administration has set standard definitions for what is in a product that bears these names.
Foods are allowed to be called USDA Organic when at least 95% of the ingredients are free from chemical fertilizers or pesticides, genetic engineering, sludge, antibiotics or irradiation in their production. A product can still be labeled “made with organic ingredients” if only 70% of the ingredients meet these standards. Organic livestock must be allowed to graze outdoors, feed organic food, and must not be exposed to large amounts of antibiotics or growth hormones.
For a food to be labeled as natural, it must be free from food colors, artificial flavors and any other synthetic substances.
Families commonly believe organic foods are more nutritious, and therefore healthier choices. Currently, the research literature does not have strong evidence that organic foods are more nutritious, or improve pregnancy outcomes. This means some studies show differences, while others do not. Generally, the studies are not well-powered (not enough people) or not well designed (not able to deal with the confounding factors) which makes it difficult for the research community to come to a consensus.
What is a confounding factor? It is something else that has an affect on the nutrient quality of a food that may or may not be related to the organic growth. For example, the nutrient quality of produce depends on the geographic location where it grows, the local soil and climate conditions, the maturity at the time of harvest, and the way it is stored. Most studies of nutrients are not able to account for all these differences. Another problem is comparing results of studies performed in different countries with different regulations and product processing. What is considered "organic" may vary.
Comparing families that purchase organic to those who do not (such as a study which looks at the differences between organic and conventional diets in pregnancy) will likely bring up differences in lifestyle in addition to the difference in diet. Consuming organic foods is associated with consuming a better diet overall. For example, in one study, pregnant women who consumed organic foods had a diet with a higher density of fiber and most nutrients, and a lower density of sodium.
In one study, consuming organic foods during pregnancy did not reduce rates of eczema, wheezing or other atopic (allergic) outcomes in the children. In another study, there was no association between consuming organic foods and the overall rate of hypospadias, a common defect.
These studies agree with a very controlled long-term feeding study of rats completed by researchers at a Danish university. The researchers controlled all aspects of the food for the rats for two years ensuring the only difference was in farming method. They controlled for geographic location of the field, timing of harvest and timing of storage. They found there were small differences in individual nutrients in the feed products, which agrees with many of the studies on difference. Yet these differences were smaller than the other issues known to affect nutrition of food such as harvest year, field location and time of harvest. They also found there were no differences in the overall health of the animals fed organic rather than conventionally grown foods.
There are similar difficulties in comparing organic to conventional dairy products. The composition of the dairy product depends on the genetic variety and breed of the animal and is strongly related to the feed - which changes in both organic and conventional farming throughout the year. For example, one study comparing dairy products found organically produced did have higher levels of protein, omega-3 fatty acids and the omega-3 to omega-6 ratio. But the biggest influence on the omega acid content was season, not the type of feed. Both feeding regimens produced milk with a higher 3/6 ratio in the summer than in the winter.
While hormones given to livestock are often blamed for early puberty, research has not been able to support a connection. Studies of bovine dairy show that human milk actually has higher levels of estrogen, and organically raised cattle produce milk with higher levels of estrogen and progesterone than their conventional counterparts. Despite this, the sex steroids given to cattle to increase lean mass are not species specific. Studies to determine safety were performed in the 70's and 80's and were based on the residual levels in the meat. It is possible the newer technology of today will find differences, but as with plant foods, a difference does not necessarily mean a difference in overall health for the consumer. More research needs to be completed.
Two ways organic foods have the most evidence to be more healthful are not necessarily related to the nutrient content. First, there is very good evidence eating organic foods reduces exposure to pesticides. In children, the main exposure to pesticides is through food. The second is that organically produced foods help stop the spread of antibiotic-resistant organisms in the food chain.
Families have different reasons for choosing to eat organic or not. A main concern about organic food is that it is more expensive to purchase. Other families feel that since the food cannot be guaranteed to be completely free of chemicals it is not worth the extra money. Some scientists feel it is unfair to recommend families absorb the higher cost of organic foods when there is a lack of quality human studies on the health differences of eating organic.
Families that choose to buy organic may do so because they prefer the flavor or to avoid as many chemicals as possible. Other families choose organic because they feel it is a more responsible way to farm and maintains a healthier environment. Some scientist feel it is unfair to encourage families to consume chemicals when it has not been proved that they provide the same health benefits as naturally grown foods.
If you want to move to organic foods, but do not have the food budget to buy all organic, start with thin skinned fruits and vegetables, or those whose skins you might eat. This is likely to have the biggest impact on reducing your exposure to pesticides.
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