I come back from the Thanksgiving holiday a bit humbled. My nieces and nephews are now the family college students, a title I once held. I found my aunt had reclaimed some of the energy, weight, and hair lost to cancer and its treatments. And my grandfather now walks with a cane. We cooked, talked, and laughed as we celebrated good food and the opportunity to gather together. We updated each other on our successes and our plans for the near future. At the end of the day, we parted with tummies full of food and hearts grateful for loved ones and for health.
It seems like any discussion of Thanksgiving includes at least a mention of food and appetite. Here are descriptions of three hormones that influence appetite:
- Leptin is known for decreasing appetite. It gives feedback to the brain about the availability of fat storage. It may also stimulate energy expenditure and autophagy. Inflammation has been identified as one of the factors causing leptin resistance.
- Ghrelin, aka The Hunger Hormone, is known for increasing appetite. It can also stimulate fat storage, inhibit apoptosis, and shifts metabolism to use carbohydrate pathways rather than fat pathways.
- Insulin is known for decreasing blood sugar and decreasing appetite. It may decrease ghrelin and increase leptin. Insulin resistance is associated with leptin resistance.
The production of these compounds and the activity of their receptors can be influenced by genetics, diet, and supplements.
Omega 3 may improve satiety. Effects of n-3 Polyunsaturated Fatty Acid Supplementation on Serum Leptin Levels, Appetite Sensations, and Intake of Energy and Macronutrients in Obese People: A Randomized Clinical Trial. The authors of this study recognized that there is conflicting evidence related to the influence of omega-3 supplements on leptin levels and leptin gene expression. So they sought to gain more understanding of those effects and their relation to appetite sensation and dietary intakes. The study involved 30 people in Iran, 18-45 years old, with a BMI of 30-40. Participants received either a placebo or three 1 g capsules of omega-3 oil, containing 180 mg of eicosapentaenoic acid (EPA) and 120 mg of docosahexaenoic acid (DHA), for 4 weeks. Although BMI and leptin levels did not significantly change over the 6 weeks, calorie intake decreased, and feeling of fullness increased.
Omega 3 may decrease cardiovascular risk. Effects of n−3 Fatty Acid Supplements in Diabetes Mellitus. This study is known as the ASCEND study. It involved 15,480 participants over age 40, diagnosed with type II diabetes and no evidence of heart disease. Participants were given a 1 g olive oil supplement as a placebo or 840 mg of omega−3 fatty acids (460 mg EPA and 380 mg DHA) for over 7 years. This study found that the group taking the omega-3 supplement had a slightly lower rate of death from vascular related events (heart attack and stroke). The recently released Cochrane study also suggested that there may be a slight decrease to CVD-related death when taking omega-3 supplements. The researchers did not find any significant benefit in the risk of heart attack, angina attack, or stroke. Basically, the group taking the omega-3 supplement wasn’t less likely to have a heart attack or stroke but the risk of dying from a heart attack or stroke was lower.
Omega 3 may improve healthy gut microbiome. A randomised trial of the effect of omega-3 polyunsaturated fatty acid supplements on the human intestinal microbiota. This study was digging beyond the observations that diets higher in omega-3 fats are associated with reduced rate of colorectal cancer, and that some types of bacteria in the colon provide protection from colorectal cancer. They wanted to see if omega-3 supplements influence the balance of bacteria in the colon. They recruited 22 people over age 50. Participants received either two 200 ml omega-3 drinks per day (2000 mg EPA and 2000 mg DHA, as the triglyceride) or four soft-gel omega-3 capsules twice a day (2000 mg EPA and 2000 mg DHA, as the ethyl ester). The assigned intervention was taken for 8 weeks. After the 8 weeks, participants were given a 12-week washout period with neither supplement. Participants then took the other intervention for 8 weeks, followed by a 12 week washout before final samples were collected. Blood and stool samples were collected at significant points in the study. This study is not a blind study because it was obvious who was getting the drink vs the capsules. The EPA and DHA content of red blood cells increased with both supplements. The amount of “good bacteria,” including Bifidobacterium, Lachnospira, Roseburia, and Lactobacillus, increased during omega-3 supplementation and levels reversed during the washout period.