Fish Rich Diet Lowers Leptin

[SteelWeaver]

This is interesting. I thought it was a good thing to have HIGH leptin levels, but I suppose that only goes for when one is on a diet, when they can't go very high anyway.

Fish Rich Diet Lowers Leptin


United Press International

Tuesday, July 2, 2002

ROCHESTER, Minn., Jul 01, 2002 (United Press International via
COMTEX) -- All things being equal -- including one's genes --
eating a diet rich in fish appears to be healthier for the heart
than eating a vegetarian diet, researchers who studied members
of an African tribe whose diet varies by village report.

The findings suggest a diet high in fish helps the body control
blood levels of leptin, a substance secreted by fat tissue. High
leptin levels have been associated with increased risk for heart
attack and stroke.

Lead author of the study, Dr. Virend K. Somers of the Mayo Clinic
in Rochester, said the results are particularly significant because
the people studied have the same genetic makeup but simply eat
different diets. Somers told United Press International leptin
levels usually increase as people gain weight but in the new
study people who ate fish continued to have low leptin levels
even as they gained weight.

Heart researchers have been interested in leptin for several
years because leptin in animals controls eating by sending a
message to the brain when sufficient food is consumed. This
"satiety" aspect of leptin also works in normal weight humans,
but as people gain weight the leptin message is muted, Somers
said. "So in obese people there are higher leptin levels because
more leptin is needed to send the message when a person is
'full.'"

The new findings indicate fish somehow "changes the
relationship between leptin and body fat and helps the body be
more sensitive to the leptin message," Somers said. Not only did
leptin levels not increase as weight increased among those
eating the fish diets, but the fish had an even more marked effect
on women, who normally have higher leptin levels than men. In
this study "women's leptin levels were half that of men on the
vegetarian diet," said Somers.

The average leptin level for men on the fish diet was 2.5
nanograms per milliliter. For women the average was 5.0 ng/mL.
Men on the vegetarian diet registered an average leptin of 11.2
ng/mL and for women it was 11.8. Somers and colleagues
studied 279 people who ate diets rich in fish and 329 who ate
vegetarian diets.

Calling the findings "very interesting," Tufts University nutrition
expert, Dr. Alice Lichtenstein also cautioned, "it is unclear how
these findings relate to Westernized societies."

Somers agreed that the populations in his study are not typical of
Americans. The subjects studied were members of a tribe living in
Tanzania. Some of the tribe members live in a village close to a
lake, while others live inland. The lake-dwelling tribe members
eat a diet that includes 300 to 600 grams of fish a day and
accounts for about a fourth of their total daily calories. The
inland-dwelling tribe members eat a vegetarian diet. Both groups
consume about 2100 calories a day.

One important factor is residents of both villages were fit and
lean -- much more fit than "the average American," said study
co-author Dr. Bradley Phillips of the University of Iowa in Ames.
"And these people were eating about three fish meals a day,
which would be pretty hard to sell to the American public."

Lichtenstein said consumers who are interested in heart-healthy
diets should stick to current American Heart Association's
recommendations to eat a diet "rich in fruits and vegetables, that
includes two servings of fish a week."

The research is reported in the July 2 issue of the journal
Circulation.

 

[anthrax]

interesting info

BTW, about leptin:

"First of all, obesity is not created equal. From the Leptin view point, there is obesity with increased and with decreased Leptin levels. The ones with increased Leptin level are associated with very low sensitivity to Leptin and they represent the majority of all cases. However, in 5 to 10% of all obesity, Leptin levels are below normal, for example, it is true for Pima Indians (Nature Med. 3:238-40, 1997). So, no matter what the reason -- low level or low sensitivity -- when Leptin does not work properly, obesity occurs.
Weight loss, no matter what the reason, results in decrease of Leptin level : when obese individuals were reduced by 10% of their initial body weight, the serum Leptin level decreased by 55%."

 

[Par Deus]

Fish oils increase sensitivity, in al likelihood, so the fact that it deceases serum levels is not really a big deal -- fish oils have been cosistently found to be anti-lipogenic.