When it comes to serious psychiatric diseases like schizophrenia, most people would agree that prevention would be the best strategy. But solid information on risk factors for schizophrenia is lacking. New research done at the CU Med School sheds some light on how genetics and environment might affect this process.
According to lead author Dr. Randy Ross, professor in the Department of Psychiatry, one simple strategy might be better choline intake for pregnant women. Brain circuits are formed in the neonatal period. The nutrient choline influences expression of certain genes during this time, and is a key player in fetal brain development.
In this study, pregnant women were supplemented with phosphatidylcholine or placebo. The infants of the choline-supplemented mothers were then supplemented with a small dose after birth. Using EEG sensors, the researchers measured the infants' brain response to specific clicking noises. As Dr. Ross notes, genes that are associated with schizophrenia control this response. Normally, infants will react to a clicking sound, but their response to a second click is inhibited. In schizophrenia, the second response is not inhibited, indicating an inability to filter sensory input.
Dr. Ross and his colleagues found that 86% of the choline-supplemented infants had the appropriate inhibited response to the clicking noise, compared to half as many in the placebo group. In other words, choline supplementation affected brain function, reducing genetic expression of a risk factor for schizophrenia.
I asked Dr. Ross the obvious question: will choline supplements "fix" existing schizophrenia? His answer was emphatically No. Pre-natal choline is important to promote the quality of brain circuitry. Boosting choline intake after the circuits are established won't be helpful. It's important to note that lack of response does not guarantee an infant will grow up to develop schizophrenia. Additional long term studies are needed to clarify whether supplemented infants develop schizophrenia at a lower rate.
While this study specifically looked at risks for schizophrenia, Dr. Ross believes that choline could also affect other problems related to brain development, such as autism or cognitive abilities. Again, long term follow up studies that track prenatal choline intake and disease processes are needed.
Where do we get choline? Egg yolks are one of the most concentrated sources in our diets. The choline-supplemented women in the study were getting the equivalent of about 3 eggs/day. Ironically, according to USDA data, per capita egg consumption has plummeted from 276 per person per year in 1976 to 167 now. If each egg contains roughly 150 mg of choline, that's a collective drop in choline intake of 45 mg/day, or 10% of recommended intake for an adult woman. The drop in choline intake for people who completely avoid eggs, or eat only egg whites would be more drastic. Other choline sources include liver, fish, soy beans/tofu, dairy products and meat.
Recent studies indicate that choline intake in the general population is below current recommendations. Meanwhile pregnant women should certainly select foods that ensure adequate choline intake. The suggested intake for a pregnant women is 450 mg/day, and that increases to 550 for women who are breastfeeding.
Better to get that choline from food. Dr. Ross notes that when gut bacteria process large doses of phosphatidylcholine from supplements the result can be a fishy body odor.