Estrogen helps control food cravings
We know estrogens have a strong effect on eating behavior. A new study from Jennifer Richard from University of Gothenburg, Sweden and colleagues sheds more light on the subject.
First, they measured the impact of the naturally-occurring estrogen cycle on eating in rats. The lower the estrogen, the more likely the rodents were to seek out food, eat more of it, and they were also more motivated by sugar. Conversely, when estrogen went up, food cravings and consumption went down.
↑ estrogen = ↓ food cravings
↓ estrogen = ↑ food cravings
Next, they investigated supplementary β-estradiol (an estrogen). One group received estradiol injections just under the skin. As you’d expect, the increased estrogen reduced food reward behavior. The next group received injections directly into the ventral tegmental area (VTA) — a key part of the brain involved in processing reward (and it contains estrogen receptors). This also led to reduced food-motivated behavior (but surprisingly, there wasn’t a change in actual food intake, body weight, or physical activity level).
Finally, they examined what happens when the ovaries are removed and natural sources estrogen are taken away. As you’d expect by this point, this lead to a lasting increase in motivation for sugar, food intake and body weight (this is often seen in women who undergo this procedure and perhaps in women who have undergone menopause).
These findings reinforce the importance of estrogen in long-term, healthy food reward behavior, and will hopefully bring us closer to understanding the best way to use supplemental estrogen — from a medical intervention perspective — to help people achieve and maintain a healthy weight.