Sci/Lay: Two epidemiology PDF available diet studies

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Hi All, Subject: Sci/Lay: Two epidemiology PDF available diet studies.

The second study I found to be the best. The first is quite good but the

full-text is little more than the abstract in Medline. The full-text does

describe the Southern Chinese who have worse diets and health. The PDF is

available.

Liu XQ, Li YH.

Epidemiological and nutritional research on prevention of cardiovascular

disease in China.

Br J Nutr. 2000 Dec;84 Suppl 2:S199-203.

PMID: 11242470 [PubMed - indexed for MEDLINE]

Below is a description of fish-eating versus vegetarian genetically

identical Tanzanian tribespersons. It is from a good journal, Circulation,

and July of this year. The PDF is available.

Fig. 1 showed that 11.3 mg/ml in fish-eating and 3 mg/ml in vegetarian were

the levels of leptin in men. For women the respective numbers were 11.8 and

5. So not only was there a large increase with of leptin with fish, there

was also an obliteration of the difference between men and women in leptin

level. This sounds positive considering women outlive men. All were a

relatively low about 20 body mass index.

Table 1, attached, shows that there were many more healthy vegetables in the

vegetarian diet. Caloric intakes varied not. Neither really took much

alcohol but the difference was significant. I find that the archives

generally have a much clearer and easier to follow copy of the attached

table in this .txt format for my attachments.

Table 2, attached, shows levels of biomarkers. Insulin was significantly

lower in the fish-eaters. Glucose levels were not, as they generally are

with CR.

It was interesting that the n3/n6 ratio of fats was much greater in those

who ate fish and this was mostly due to increased n3 fats. I also liked the

suggestion that vegetarians have little health advantage when other

confounding better health indicators are factored out. Also, I liked the

text’s conclusion:

“In conclusion, we show that a diet rich in fish is associated with lower

plasma leptin concentrations, independent of body fat or BMI, suggesting

that this kind of diet may improve leptin sensitivity. In subjects on a fish

diet, leptin levels are even lower than those documented in persons

heterozygous for a frameshift mutation in the ob gene.3 The low leptin in

subjects on a fish diet is not necessarily associated with increases in BMI

or body fat. These findings may have implications for understanding the

reduced cardiovascular risk in subjects on a fish-rich diet.”

Winnicki M, Somers VK, Accurso V, BG, Puato M, Palatini P, etto

P.

Fish-rich diet, leptin, and body mass.

Circulation. 2002 Jul 16;106(3):289-91.

PMID: 12119240 [PubMed - indexed for MEDLINE]

“………..CONCLUSIONS: British vegetarians have low mortality compared with the

general population. Their death rates are similar to those of comparable

non-vegetarians, suggesting that much of this benefit may be attributed to

non-dietary lifestyle factors such as a low prevalence of smoking and a

generally high socio-economic status, or to aspects of the diet other than

the avoidance of meat and fish.”

“One tribe consumes freshwater fish as their main diet component (n=279),

and the other tribe consumes a primarily vegetarian diet (n=329). In

multivariate analysis, plasma leptin levels were associated with type of

diet (F=14.3, P<0.001), independent of age, body mass index, body fat,

alcohol consumption, or insulin. Both male (2.5+/-2 [fish diet] versus

11.2+/-2.4 [vegetarian diet] ng/mL, P=0.017) and female (5.0+/-1.9 [fish

diet] versus 11.8+/-1.4 [vegetarian diet] ng/mL, P=0.007) fish eaters had

lower plasma leptin levels than did their vegetable diet counterparts, even

though body mass index values were virtually identical. CONCLUSIONS: A diet

rich in fish is associated with lower plasma leptin, independent of body

fat. These findings may have implications for understanding the reduced

cardiovascular risk in subjects on a high-fish diet.”

PMID: 12119240 [PubMed - indexed for MEDLINE]

“………..Males consuming the fish diet were slightly younger, used less

alcohol, and had similar body fat compared with their vegetable diet

counterparts. Similar relationships were present in women, except for

slightly higher body fat in the fish-eating group. In addition, women on a

fish diet had lower insulin levels but similar glucose levels compared with

their vegetarian diet counterparts (Table 2).

Total n-3 fatty acids (9.7±2.9% [fish diet] versus 3.5±1.2% [vegetarian

diet] of plasma lipids, P<0.001) were higher in fish eaters (n=53) than in

vegetable eaters (n=53). The opposite was observed regarding total n-6 fatty

acids (25.8±4.8% [fish diet] versus 33.1±5.5% [vegetarian diet] of plasma

lipids, P<0.001), as reported previously.11

In univariate analysis, in all men from both subgroups, leptin levels were

related to alcohol consumption (r=0.15, P=0.041) and insulin levels (r=0.46,

P<0.001) but not to BMI or body fat. In all women, leptin levels were

related only to insulin levels (r=0.57, P<0.001). However, in the fish diet

subgroup, there was a correlation between plasma leptin levels and both BMI

(r=0.22, P=0.009) and body fat (r=0.27, P=0.001).

In multivariate analysis, plasma leptin levels were independently associated

with type of diet (F=14.3, P<0.001). Both male (Figure, panel A) and female

(Figure, panel fish eaters had lower plasma leptin levels than did their

vegetable diet counterparts, even though BMIs were virtually identical.

Plasma insulin levels were strongly and independently associated with plasma

leptin levels for all groups or subgroups studied (P<0.001 for all

comparisons). Leptin levels were also independently associated with alcohol

consumption in males (P=0.025) and females (P<0.001) consuming vegetable

diets. We found no independent association of plasma leptin with BMI in any

subgroup

and a weak association of plasma leptin with body fat in fish-eating women

only (F=2.12, P=0.035)………….

In contrast to other studies,4,12 the present study was unable to

demonstrate any independent relationship between plasma leptin and body fat

composition, except for a very weak positive association in fish-eating

women. Overall, these data suggest that a fish diet is accompanied by lower

leptin and may alter the usual feedback relationships between leptin levels

and body fat and that plasma leptin levels do not always reflect BMI or the

amount of body fat.

Our findings may have relevance in understanding the relationship between a

predominantly fish diet and cardiovascular disease. Higher leptin

concentrations have been prospectively implicated as an independent risk

factor for stroke, coronary artery disease, and myocardial infarction.5–7

Prospective studies have shown that a diet rich in fish or fish oil is

related to a low incidence of cardiovascular disease.13 The mechanisms of

the protective effect of fish oil on cardiovascular risk have been

attributed mainly to the high concentration of n-3 polyunsaturated fatty

acids and their antithrombotic action and modification of immunological

processes.14,15 The fish diet that we have studied is also associated with

lower blood pressure and a favorable lipid profile.11 We speculate that an

additional potential benefit of a fish-rich diet on cardiovascular risk may

be the reduction in plasma leptin concentrations.

There are several limitations of the present study. First, only lean black

Africans were studied. Different relationships between fish diets and leptin

may exist in obese subjects and in different races. Second, other unknown

dietary or behavioral factors may contribute to the apparent effect of the

fish diet on leptin concentrations. However, the food questionnaire used was

validated by previous nutrition analyses carried out in Tanzania.11 Third,

underlying genetic factors may contribute to the difference in plasma leptin

concentrations. However, both dietary groups belong to the same tribe, speak

the same dialect, live near each other, and have similar calorie intakes,

lifestyles, and BMI values. The only difference was the type of diet.

In conclusion, we show that a diet rich in fish is associated with lower

plasma leptin concentrations, independent of body fat or BMI, suggesting

that this kind of diet may improve leptin sensitivity. In subjects on a fish

diet, leptin levels are even lower than those documented in persons

heterozygous for a frameshift mutation in the ob gene.3 The low leptin in

subjects on a fish diet is not necessarily associated with increases in BMI

or body fat. These findings may have implications for understanding the

reduced cardiovascular risk in subjects on a fish-rich diet.”

Cheers, Al.

Alan Pater, Ph.D.; Faculty of Medicine; Memorial University; St. 's, NF

A1B 3V6 Canada; Tel. No.: (709) 777-6488; Fax No.: (709) 777-7010; email:

apater@...