A new study, just published in the Journal of the American Medical
Association (JAMA), found that a high-fat, ketogenic diet markedly
increased LDL bad cholesterol and lowered HDL good cholesterol in
American children who had been following the diet for six months
to two years.*
“This study directly refutes the claim made by the late Dr.
Robert Atkins that, as long as carbohydrate intake is kept very
low, diets high in saturated fat and cholesterol do not adversely
impact blood lipids,” states Dr. Jay Kenney, Nutrition Research
Specialist at the Pritikin Longevity Center® & Spa.
In the study, the 141 children, all of whom had epilepsy and difficult-to-treat
seizures, had been directed to adopt a high-fat diet because, interestingly,
high-fat diets do indeed decrease seizure frequency.
Children’s arteries
But pediatric scientists at Johns Hopkins Medical Institutions in
Baltimore were concerned that such a diet, though beneficial for
seizure control, might in fact be harming the children’s coronary
arteries, promoting inflammation and triggering the formation of
artery-clogging plaque.
So they launched a study to see how children’s cholesterol
and triglyceride levels were affected by ketogenic diets. (A ketogenic
diet is one that is so low in carbohydrates, the premium fuel source
for the brain, that the body, in search of another fuel source,
breaks down fat into compounds, like acetone, that are called ketones.)
LDL, triglycerides skyrocket
At the beginning of the study and then 6 months, 12 months, and
24 months later, the Johns Hopkins researchers took blood measurements
of the kids. After just six months, the high-fat ketogenic diet
significantly increased both total and LDL cholesterol. Total cholesterol
shot up from an average 174 to 232. LDL rose from 99 to 148. Triglycerides
went up 60%, from 96 to 154. HDL, the good cholesterol, fell from
56 to 49.
Adverse changes in blood lipid levels persisted in the children
after 12 and 24 months.
“The results of this study confirm decades of research showing
that a diet high in saturated fat and cholesterol clogs arteries,
and it specifically refutes any claims that limiting carbohydrates
on such a diet prevents negative changes in cholesterol and triglyceride
levels,” asserts Dr. James Barnard, professor of physiological
science at UCLA and author of dozens of studies on the relationship
between diet, exercise, and disease.
Research on adults
In particular, the study echoes results of research on adults, published
in August 2002 in Preventive Cardiology. Scientists assigned 100
overweight men and women to one of four diets, one of which was
a high-fat, low-carbohydrate diet, similar to the one the children
followed in the Johns Hopkins study. Another was a very low-fat
diet rich in unrefined carbohydrates like fruits, vegetables, and
whole grains, much like the Pritikin Eating Plan.
After one year, the men and women on the high-fat, low-carb diet
lost weight (13% of their body weight), but at the price of increased
cardiovascular risk factors. Triglycerides rose, as did LDL cholesterol,
total cholesterol, clotting factors, and homocysteine levels. HDL
fell.
By contrast, the men and women following the low-fat, Pritikin-style
diet lost more weight (18% of body weight) and, at the same time,
dramatically improved risk factors for heart disease. LDL cholesterol
dropped, on average, 52%. Total cholesterol fell 39%. Triglycerides
dropped 39%, and HDL cholesterol rose 9%.
Sudden death of adolescent
In another just published report in Southern Medical Journal (September
2003), physicians from the Department of Child Health at the University
of Missouri described a 16-year-old girl who had recently died from
sudden cardiorespiratory arrest.
Two weeks previous, she had started a weight loss plan using a low-carbohydrate,
high-protein, high-fat diet. She had carefully followed the diet,
eating meat, cheese, and salads without fasting. Her mother had
been on the same diet.
She collapsed while at school. Attempting to resuscitate the teenager,
the emergency team noted severe electrolyte imbalances, potentially
caused by the diet, wrote the University of Missouri physicians.
No other causes for the cardiac arrest were identified. The girl
had been in good health and had no known history of medical problems.
In an interview, one of the authors, Dr. Paul Robinson, explained
that he and his colleagues had published the paper to alert other
doctors to the potential risks of the Atkins diet and other high-fat
diets.
In the report, he and associates concluded: “In light of the
previous reports of mortality related to liquid protein diets and
the lack of information on electrolyte and physiologic changes during
low-carbohydrate, high-protein diets, we do not recommend such dieting
regimens.”
* JAMA, 2003. 290: 912-920.
|
