11 December 2013
Poor diet shown to have dramatic effects on sperm and future health of offspring
by Will Parker
A startling new study from McGill University suggests that a father's diet before conception plays a major role in fetus development and the offspring's future predisposition to disease. The researchers say that significant alterations to the sperm epigenome triggered by diet and lifestyle choices should raise serious concerns about the long-term effects of current Western diets.
The new work adds to the rapidly expanding sphere of knowledge about epigenetics. Epigenetic codes are thought of as an extra layer of biochemical instructions in DNA that can evolve more quickly than an organism's regular genetic code. For example, a study published earlier this year showed how a father's exposure to stress could affect his offspring's responses to stress and future risk of neuropsychiatric diseases.
The new study, published in Nature Communications, focused on folate (vitamin B9), which is found in a range of green leafy vegetables, cereals, fruit and meats. It's well established that in order to prevent miscarriages and birth defects, mothers need to get adequate amounts of folate in their diet. But how a father's diet can influence the health and development of offspring has received little attention.
Now, research by Sarah Kimmins and colleagues shows for the first time that the father's folate levels may be just as important to the development and health of offspring as are those of the mother.
Working with mice, the researchers compared the offspring of fathers with insufficient folate in their diets with the offspring of fathers whose diets contained sufficient levels of the vitamin. They found that paternal folate deficiency was associated with an increase in birth defects of various kinds in the offspring, compared to the offspring of mice whose fathers were fed a diet with sufficient folate.
"We were very surprised to see that there was an almost 30 percent increase in birth defects in the litters sired by fathers whose levels of folates were insufficient," said co-researcher Romain Lambrot. "We saw some pretty severe skeletal abnormalities that included both cranio-facial and spinal deformities."
Kimmins group shows that there are regions of the sperm epigenome that are sensitive to life experience and particularly to diet. "The epigenome is like a switch, which is affected by environmental cues, and is involved in many diseases including cancer and diabetes," explained Kimmins. "The epigenome influences the way that genes are turned on or off, and hence how heritable information gets passed along... this information is in turn transferred to a so-called epigenomic map that influences development and may also influence metabolism and disease in the offspring in the long-term."
Although it has been known for some time that there is a massive erasure and re-establishment that takes place in the epigenome as the sperm develops, this study suggests that along with the developmental map, the sperm also carries a "memory" of the father's environment and possibly even of his diet and lifestyle choices.
Kimmins suggests that fathers should pay as much attention to their lifestyle and diet before they set out to conceive a child as mothers do. "Despite the fact that folic acid is now added to a variety of foods, fathers who are eating high-fat, fast food diets or who are obese may not be able to use or metabolize folate in the same way as those with adequate levels of the vitamin," says Kimmins. "We now know that this information will be passed on from the father to the embryo with consequences that may be quite serious."
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Source: McGill University