Sunday, June 19, 2011

Coconuts and grain fed meat have different effects on heart disease

In chapter eight of GCBC Mr. Taubes tells us about the Tokelau Island Migration Study. Unfortunately there's always more than one way to interpret an observational study.

The original diet with no western diseases:
  •  coconuts
  •  fish
  • breadfruit
New diet of those who remained on the island - more western disease:
  •  less coconuts but still a lot
  •  less fish but still a lot
  •  seven fold increase in sugar
  •  six fold increase in flour
  •  canned meat
  •  frozen foods
New diet of those who left the island - much more western disease:
  •  virtually no coconuts or fish
  •  a lot of meat, bread, potatoes and sugar
Taubes assumes all sources of saturated fat have the same effect on health. And he concludes that since saturated fat and serum cholesterol levels went down and sugar and white flour went up and heart disease went up THEREFORE saturated fat and serum cholesterol are unrelated to heart disease and sugar and white flour are the true causes.

But there's another way to interpret the evidence. Coconuts and fish are healthy sources of saturated fat. Studies have shown that coconuts (which are high in lauric acid and polyphenols) improve the HDL:LDL ratio. And fish is high in omega-3 fatty acids. On the other hand, grain fed meat is low in lauric and omega-3 fatty acids and contains no polyphenols. And unlike coconuts, grain fed meat and dairy makes the HDL:LDL ratio worse.
 http://www.ncbi.nlm.nih.gov/pubmed/12600847

Studies show that sugar increases triglycerides and decreases HDL and it's associated with metabolic syndrome, so it's bad for heart disease. BUT IF SUGAR WAS THE ONLY PROBLEM THEN PEOPLE WHO GO ON A TRADITIONAL ATKINS DIET SHOULD BE HEART ATTACK PROOF. However, according to the most favorable study that actually measures mortality, high saturated fat diets are no better than the standard American diet and according to the least favorable study diets high in saturated fat from grain fed meat and dairy (similar to what Dr. Atkins recommended) show 81% more heart attacks and 48% more all-cause mortality.

Low-carbohydrate-diet score and the risk of coronary heart disease in women.
http://www.ncbi.nlm.nih.gov/pubmed/17093250
Mediterranean and carbohydrate-restricted diets and mortality among elderly men
http://www.ncbi.nlm.nih.gov/pubmed/20826627

Even in the most favorable study for high saturated fat diets, when low carbohydrate scores were equal the people who ate less animal fat (most likely from grain fed meat and dairy) had significantly less heart disease.