Authors: Mary Enig
Indian Railway Workers
In 1967, Dr. S. L. Malhotra published a study of Indian railway employees in the
British Heart Journal
. He found that heart disease was seven times more common among workers in Madras compared to those in Punjab. Yet the Punjabi workers ate ten to twenty times more fat (and smoked eight times as much) as those in Madras. And the Punjabi workers, eating their high-fat diet, also lived twelve years longer than the largely vegetarian workers in Madras.
The Framingham–Puerto Rico–Honolulu Study
In an even larger study conducted by the National Institutes of Health, 16,000 healthy middle-aged men in Framingham, Massachusetts; Puerto Rico; and Honolulu answered questions about their eating habits. Six years later, in 1981, the researchers compared the diets of those who had had heart attacks with those who had not.
The most significant finding was the fact that the heart attack victims had eaten
more polyunsaturated oils
than the other group. This result is clearly contrary to the assumptions of the lipid hypothesis.
Review of Many Studies
In 1998, the
Journal of Clinical Epidemiology
published a review of 27 studies, involving over 150,000 individuals, that looked at the relationship between diet and heart. In three groups, the patients had eaten more animal fat than the controls. In one group, they had eaten less. In all the other groups, researchers found
no difference
in animal fat consumption between people with heart disease and those without. What’s more, in three groups the patients had eaten more vegetable oil than the controls. In only one group had patients eaten less vegetable oil than the control group.
Taken as a whole, then, this research did not—and does not—support the assumption that high-fat foods cause heart attacks. Nevertheless, in 1989 the American Heart Association and the National Heart, Lung, and Blood Institute issued a joint statement that touted many of these same studies as “showing the link between diet and CHD.” And, on that basis, they condemned saturated fats and promoted polyunsaturated oils.
Should You Avoid Animal Fat If You’ve Had a Heart Attack?
The medical literature actually contains only two studies involving humans that compared the
outcome
(not just indicators like cholesterol) of a diet high in animal fat with that of a diet based on vegetable oils. Both studies showed that animal fats actually protect you from heart disease.
The Anti-Coronary Club project, launched in 1957 and published in 1966 in the
Journal of the American Medical Association,
compared two groups of New York businessmen, aged 40 to 59 years. One group followed a “Prudent Diet” consisting of corn oil and margarine instead of butter, cold breakfast cereals instead of eggs, and chicken and fish instead of beef. A control group ate eggs for breakfast and meat three times per day.
The final report noted that the average serum cholesterol of the Prudent Dieters was 220 mg/dl (milligrams per 1/10 liter), compared to 250 mg/dl in the eggs-and-meat group. But there were
eight
deaths from heart disease among the Prudent Dieters—and
none
among those who ate meat three times a day.
In a study published in the
British Medical Journal,
1965, researchers divided patients who had already had a heart attack into three groups. One group received polyunsaturated corn oil, one got monounsaturated olive oil, and the third was given saturated animal fats.
After two years, the corn oil group had 30 percent lower cholesterol—but only 52 percent remained alive. The olive oil group fared little better: only 57 percent were alive. But among the group who ate mostly animal fat,
75 percent
were alive.
Unfortunately, the proponents of the lipid hypothesis have ensured that the many studies that refute the hypothesis do not get publicity, so that few doctors know about this research. As a result, heart attack patients in the U.S. are invariably told to avoid animal fats.
Recent Studies Agree
One criticism of the studies cited focuses on the fact that they are old. But recent studies confirm the same. For example, the results of a study conducted by researchers in Denmark and published in the
European Journal of Clinical Nutrition
, 2002, indicated no association between dietary patterns and coronary heart disease. The study looked at the diets of patients admitted to the hospital for diagnosis of heart disease. Patients were divided into three groups: two groups ate diets that were “healthy” according to establishment standards—they avoided animal fats and frequently ate whole grains, fruit, and vegetables. The third group consumed a so-called Western diet with a lot of meat, butter, and white bread. Again, the study indicated no association between dietary patterns and coronary heart disease,
even though the otherwise healthy “Western” diet contained white bread.
A Swedish study published in the
British Journal of Nutrition
, 2004, found that consumption of milk fat (that is, butterfat) was
negatively
associated with the risk factors for heart disease and also for actual heart attack. In other words, butterfat
protects
against heart disease.
Myth #2: High Cholesterol Causes Heart Disease
The idea that high levels of cholesterol in the blood cause heart disease is an axiom today. Yet if you look at the evidence—even evidence presented as proving the lipid hypothesis—you’ll see that there is much data refuting it.
The Framingham Study
The first major government-sponsored study on heart disease was the 40-year Framingham Study, which began in 1948. Researchers looked at 500 residents of this Massachusetts town in an ongoing investigation of all the factors that might contribute to heart disease. An important early result of the study apparently indicated that high cholesterol was a risk factor for heart disease.
However, a follow-up study published 16 years later revealed that there was very little difference between the cholesterol levels of people who had heart attacks and those who did not. In fact, almost half of those who had a heart attack had
low
cholesterol.
Still another analysis, carried out 30 years after the original one, found that men older than 47 died just as often whether their cholesterol was high
or
low. Since most heart attacks occur in people over 47, this raises the question of whether cholesterol really makes any difference.
An even more startling result from this 30-year follow-up study was that people whose cholesterol had
decreased
over that period had a higher risk of dying than those whose cholesterol had
increased.
The researchers wrote that “For each 1 mg/dl drop in cholesterol, there was an 11 percent increase in coronary and total mortality.” That is, deaths from heart disease and all other causes increased by
11 percent
for each 1 percent drop in cholesterol in the blood.
Yet a 1990 joint statement by the American Heart Association and National Heart, Lung and Blood Institute, published in the journal
Circulation
, claims that “The results of the Framingham study indicate that a 1 percent reduction…of cholesterol [corresponds to] a 2 percent reduction in CHD risk.”
You may find this hard to believe, but it’s true. And this is only one example of the way data that actually disprove the lipid hypothesis are frequently cited as supporting it.
The International Atherosclerosis Project
The lipid hypothesis could have been laid to rest as far back as 1968, with the publication of the results of the International Atherosclerosis Project in the journal
Laboratory Investigations
. Researchers performed detailed autopsies on 22,000 corpses in 14 nations. This study showed the same degree of atheroma (fatty plaques that block arteries) in all parts of the world—in populations that consumed large amounts of fatty animal products and those that were largely vegetarian; and in populations that suffered from a great deal of heart disease and in populations that had very little or none at all. Furthermore, the researchers found just as much artery blockage in people who had low levels of cholesterol compared to those whose cholesterol was high.
For Women: High Cholesterol Is Better
A truly surprising result of all studies involving women is the finding that in women, high cholesterol levels—even as high as 1,000 mg/dl—are
not
a risk factor for heart disease. In fact, for women low cholesterol is
more
dangerous than high cholesterol. This was the conclusion of a workshop that looked at every study involving cholesterol and women, held at the National Heart, Lung, and Blood Institute and published in the journal
Circulation
in 1992.
For example, a 1989 Parisian study published in
The Lancet
found that those who live the longest are old women with very high cholesterol levels. Women with very low levels had a death rate over five times higher!
And more recently, in the
British Medical Journal,
2003, researchers at the University of British Columbia concluded that statin drugs, which lower cholesterol, offer no benefit to women for preventing heart disease.
Canada: No Link
Although there is a very slight association between high cholesterol and greater risk of heart disease among American men, this connection doesn’t exist for Canadian men. This was the finding of the Quebec Cardiovacsular Study, published in the
Canadian Journal of Cardiology
in 1990. Researchers studied almost 5,000 healthy middle-aged men for 12 years. They explained away their results by claiming that more than 12 years were necessary to see the harmful effects of high cholesterol levels—even though the Framingham results showed clearly that this was not the case.
Russia: Low Cholesterol = Increased Risk
A study carried out by a research team from the Russian Academy of Medical Sciences in St. Petersburg and published in the journal
Circulation
, 1993, found that it was
low
levels of LDL (the “bad” cholesterol that we’re always told to keep as low as possible) that were associated with
increased
risk of heart disease. Nor was this higher risk the result of lower levels of HDL (the “good” cholesterol), for the people with low LDL were the ones with the highest HDL levels.
The U.S. Government and LDL
We’ve described just a few of the medical studies reporting evidence that contradicts the lipid hypothesis. Yet
Diet and Health,
an official review of the research published by the National Research Council in 1990, asserts that LDL is the most important risk factor for heart disease, and in support of this statement, cites studies whose results do not, in fact, prove the relation between cholesterol and heart disease at all.
For example,
Diet and Health
cites a 1977 report from Framingham as evidence that high levels of LDL are dangerous. But one conclusion of this study is actually that “LDL-cholesterol…is a marginal risk factor” for people over 50. In fact, Framingham investigators found that women over 70 had a greater risk of heart disease if their LDL was
low.
The Latest Research
The research cited in official government documents dates back to the early 1970s. What can more recent research tell us?
The Honolulu Heart Program
A report published in
The Lancet
, 2001, as part of the Honolulu Heart Program, an ongoing study, looked at lowering cholesterol in the elderly. Researchers compared changes in cholesterol concentrations over 20 years with mortality from all causes. The results completely contradict the lipid hypothesis. Said the researchers, “Our data accords with previous findings of increased mortality in elderly people with low serum cholesterol, and show that…the earlier that patients start to have lower cholesterol concentrations, the greater the risk of death…” That is, when people maintain low levels of cholesterol in their blood over a long period of time—for example, by eating the kind of low-fat diet that government agencies recommend—their risk of death from all causes will
increase.
No Benefit from Cholesterol-Lowering Drugs
Studies carried out during the last 15 years have focused on the effects of cholesterol-lowering drugs. An analysis of 44 trials involving almost 10,000 patients was published in the
American Journal of Cardiology
, 2003. The investigators found that the death rate among three groups of patients—one taking Lipitor (a very strong cholesterol-lowering drug), one taking other cholesterol-lowering drugs, and one taking nothing—was identical.
Myth #3: High-Fat Foods Increase Blood Cholesterol
A key concept behind the lipid hypothesis is that cholesterol levels vary in different people because they eat different foods. This notion rests on the assumption that the levels of cholesterol in the blood are high in people who eat large amounts of food high in fats, especially animal fats.
Again, however, the results of a great deal of research completely oppose this idea.
Framingham: No Connection
During the early stages of the Framingham study, in the 1950s, researchers asked nearly 1,000 people about their eating habits. They found no connection at all between the food they ate and their cholesterol levels. The authors of the study noted that, although there was “a considerable range” of blood cholesterol levels among the participants, whatever might explain this variation, it was “not the diet.”