High-Exercise protective for CVD?

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Evidence that more exercise IS protective against cardiovascular disease?

Regular Walking Protects The Masai -- Who Eat High Fat Diet -- From

Cardiovascular Disease

Masai men. (Credit: iStockphoto/Robin Camarote)

ScienceDaily (July 18, 2008) — Scientists have long been puzzled by

how the Masai can avoid cardiovascular disease despite having a diet

rich in animal fats. Researchers at Karolinska Institutet believe that

their secret is in their regular walking.

There is strong evidence that the high consumption of animal fats

increases the risk of developing cardiovascular disease. Many

scientists have therefore been surprised that the nomadic Masai of

Kenya and Tanzania are seldom afflicted by the disease, despite having

a diet that is rich in animal fats and deficient in carbohydrates.

This fact, which has been known to scientists for 40 years, has raised

speculations that the Masai are genetically protected from

cardiovascular disease. Now, a unique study by Dr Mbalilaki in

association with colleagues from Norway and Tanzania, suggests that

the reason is more likely to be the Masai's active lifestyle.

Their results are based on examinations of the lifestyles, diets and

cardiovascular risk factors of 985 middle-aged men and women in

Tanzania, 130 of who were Masai, 371 farmers and 484 urbanites. In

line with previous studies, their results show that the Masai not only

have a diet richer in animal fat than that of the other subjects, but

also run the lowest cardiovascular risk, which is to say that they

have the lowest body weights, waist-measurements and blood pressure,

combined with a healthy blood lipid profile.

What sets the Masai lifestyle apart is also a very high degree of

physical activity. The Masai studied expended 2,500 kilocalories a day

more than the basic requirement, compared with 1,500 kilocalories a

day for the farmers and 891 kilocalories a day for the urbanites.

According to the team, most Westerners would have to walk roughly 20

km a day to achieve the Masai level of energy expenditure.

The scientists believe that the Masai are protected by their high

physical activity rather than by some unknown genetic factor.

" This is the first time that cardiovascular risk factors have been

fully studied in the Masai, " says Dr Mbalilaki. " Bearing in mind the

vast amount of walking they do, it no longer seems strange that the

Masai have low waist-measurements and good blood lipid profiles,

despite the levels of animal fat in their food. "

http://www.sciencedaily.com/releases/2008/07/080718075357.htm

Journal reference:

Daily energy expenditure and cardiovascular risk in Masai, rural and

urban Bantu Tanzanians

Aneth Mbalilaki 1*, Zablon Masesa 2, Sigmund Bjarne Strømme 3,

Arne Torbjørn Høstmark 4, Jan Sundquist 1, Per Wändell 1, Annika

Rosengren 5 and Mai-Lis Hellenius 6

1 Karolinska Institutet, Sweden

2 Bugando Hospital, Tanzania, United Republic of

3 Norwegian School of Sport Sciences,, Norway

4 Section of Preventive Medicine and Epidemiology, University of Oslo,

Norway, Norway

5 5Department of Medicine, Sahlgrenska University Hospital/Östra,

Gothenburg, Sweden, Sweden

6 Karolinska Institutet, Norway

* To whom correspondence should be addressed. E-mail:

aneth182@....

Accepted 6 May 2008

* Abstract

Background Several studies have revealed that the Masai, pastoralists

in Tanzania, have low rates of coronary heart disease (CHD) despite a

diet high in saturated fat. It has also been suggested that they may

be genetically protected. Recent studies detailing other potential

protective factors, however, are lacking.

Methods A cross-sectional investigation of 985 Tanzanians men and

women (130 Masai, 371 rural Bantu and 484 urban Bantu) with mean age

46.0 [sD 9.3]. Anthropometric measures, blood pressure, serum lipids,

and the reported dietary pattern and physical activity level were

assessed.

Results Eighty two percents of Masai subjects reported a high fat/low

carbohydrate intake, whereas 77% of the rural Bantu subjects reported

a low fat/high carbohydrate intake, and a high fat/high carbohydrate

intake was the main dietary pattern of the urban Bantu group as

reported by 55%. The most conspicuous finding for the Masai was the

extremely high energy expenditure, corresponding to 2565 kcal/day over

basal requirements, compared to 1500 kcal/day in the rural and 891

kcal/day for the urban Bantu. Mean body mass index among the Masai was

lower than among the rural and urban Bantu. Mean systolic blood

pressure of the Masai was also lower compared to their rural and urban

Bantu counterparts. The Masai revealed a favourable lipid profile.

Conclusion The potentially atherogenic diet among the Masai was not

reflected in serum lipids and was offset probably by very high energy

expenditure levels and low body weight.

Key terms: Masai, Bantu, energy expenditure, diet, cardiovascular disease.