Tuesday, September 2, 2008

Insulin, Leptin and fish!

If you have been following Lyle's series on the Hormones of Bodyweight Regulation you will be familiar with the role of Leptin

Leptin signals to the brain that the body has had enough to eat, or satiety. A very small group of humans possess homozygous mutations for the leptin gene which leads to a constant desire for food, resulting in severe obesity. This condition can be successfully treated by the administration of recombinant human leptin.[1] Thus, circulating leptin levels give the brain input regarding energy storage so it can regulate appetite and metabolism. from wiki

Here is an interesting study which looks at Leptin and the way in which fatty fish, in the context of a calorie restricted diet, affects it:

Three servings a week of fatty fish included in an energy-restricted diet appears to be a valid strategy for specifically improving insulin sensitivity and leptin levels

Specific insulin sensitivity and leptin responses to a nutritional treatment of obesity via a combination of energy restriction and fatty fish intake.


Background Nutritional strategies to treat obesity often influence neuroendocrine factors related to body weight control. The present study aimed to investigate whether the inclusion of three fatty fish servings per week within a hypocaloric diet may have specific healthy effects on insulin and leptin functions. Methods Thirty-two subjects (body mass index = 31.6 +/- 3.5 kg m(-2)) aged 36 +/- 7 years, were assigned to a control or fish-based energy-restricted diet over an 8-week period. Anthropometry, body composition, lipid profile, leptin and insulin values were measured at the start and at the end of the dietary intervention. Results Both experimental diets resulted in a similar mean weight loss (control = 5.3 +/- 2.6% versus fish-based = 5.5 +/- 2.5%; P = 0.783). A significant reduction in insulin resistance, as determined by the homeostatic model assessment index (HOMA-IR = insulin x glucose/22.5), was observed after the fish-based intervention. The change in circulating leptin was higher in the fish-based diet compared to the control group. Sixteen percent of the variability in the change of adjusted-leptin could be explained (P = 0.034) by the HOMA index change and the type of diet. Conclusions Three servings a week of fatty fish included in an energy-restricted diet appears to be a valid strategy for specifically improving insulin sensitivity and leptin levels in obese subjects, which could involve a better body weight regulation after a nutritional intervention period.

5 comments:

Martin Berkhan said...

Interesting. Nice find, Chris.

b said...

Good intell and furtherance of Lyle's leptin discussion.

Which are "fatty fish"? Are they available at the grocery store?

To google I go ...

Chris said...

Fatty fish usually means salmon, mackeral, sardines....

Anonymous said...

The study is misleading. Leptin function first and foremost is survival and managing energy utilization at the hypothalamus. If you eat a hypocaloric diet you are going against leptin regardless of the source (unless it is HFCSwhich leptn cant control because it is a liver toxin and the brain never sees it See Dr Lustig youtube video) Anyone who eats a hypocaloric diet will gain it all back because of leptin. The key to mastering leptin is understanding how it works on an evolotionary level and then institute it into a sequence that the individual finds itself in. If that person is obese and looking to loose weight the key is eating three meals a day and never eating passed 7 PM. And avoid carbs like the plagued at dinner. Why? because leptin spikes two hrs after your last insulin peak at dinner. Insulin is released in a biphasic way. Once insulin falls leptin rises and around midnight it enters the POMC neurons of the hypothalamus (if your not resistant) and sets the metabolic rate gas pedal (thyroid)to burn fats in stage three and four sleep so you burn fats at night. This hormone is designed to work with melatonin but with all the artificial light we have since 1925 in all cities that has gone by the way side. SO managing leptin in the face of an all summer time situation with round the year carbs is even more critical. Omega 3 fishes are important but not what is shown in this study. The design of it shows they are clueless to how this hormone works. And I am a neurosurgeon who knows how it works. Nothing hurts us more than bad info. See Ancel Keys.

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Lepin is the key to a successful bodyweight regulation so i invite every one to use it !