Risk factors for cardiac mortality

Great post at Hyperlipid.

The whole article is interesting, but the graph below is the kicker:



Notice that as HbA1c increases, particularly over about 6.2%, the risk of a cardiac episode increases dramatically.

Also notice that there is no indication that high cholesterol with a low HbA1c increases the risk of cardiac mortality.

In other words, an important goal for any heart disease prevention diet should be to minimize HbA1c. How do you do that? Minimize blood glucose -- and the most effective solution there is to reduce simple carbs and increase fat.

Caffeine and cocoa

One of the goals of the Paleo diet is to reduce the level of insulin in the body.  Insulin is a pro-aging hormone; it encourages excess energy to be stored as fat, and acts to inhibit lipolysis.  One of the side-effects of a low-carb diet is increased insulin resistance, which can lead to higher levels of insulin and larger peaks in blood glucose (BG) levels (high BG levels are worth avoiding because they can damage many internal systems, particularly nerves).

[[MORE]]Maintaining insulin sensitivity, or even increasing it, should be part of a comprehensive Paleo program.  There are many ways to do that, but I thought I would mention two that might be of interest: caffeine and cocoa.  In addition to improving insulin sensitivity, caffeine also decreases TNF-alpha, which lowers inflammation (which should, in theory, also be anti-cancer).  Cocoa contains not just caffeine, but also flavonoids, and cocoa consumption has been documented as having a strong inverse association with mortality from heart disease.

More details at Dr. T’s Nephropal blog:
http://nephropal.blogspot.com/2009/10/beans-coffe-and-cacao.html

Part of what this means to me is that drinks with coffee or tea or cocoa and cream, are acceptable on a Paleo diet not just for their low-carb, high-fat content, but because of the caffeine and flavonoids too.

Here's a link to a study that supports the idea that a low-carb diet increases insulin resistance:

http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=7895958 

As it says in the abstract: "Studies in both humans and experimental animals indicate that the adaptive (phenotypic) response to low-carbohydrate intake is insulin resistance."

What happens with a low-carb diet is that with lower levels of BG, muscles adapt to burning fat as fuel.  Then, in order to conserve glucose for areas like the brain, the muscles become insulin resistant.

The often-neglected issue with the high-carb Kitavans is that they have a high sensitivity to insulin that's derived directly from their genetics; that's how they can get away with a diet like that and remain healthy.  Most people don't share those genes.

Here are links to a few more related papers:

http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=9288547

http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=10889799

Here are a few references for coffee and cocoa/chocolate (low adiponectin is associated with insulin resistance):

Williams, CJ, et al: Coffee consumption is associated with higher plasma adiponectin concentrations in women with or without type 2 diabetes: a prospective cohort study. Diabetes Care. 2008 Mar;31(3):504-7.

Janszky I, Mukamal KJ, Ljung R, Ahnve S, Ahlbom A, Hallqvist J: Chocolate consumption and mortality following a first acute myocardial infarction: the Stockholm Heart Epidemiology Program. J Intern Med. 2009 Sep;266(3):248-57.

Ding, E, et al: Chocolate and Prevention of Cardiovascular Disease: A Systematic Review. Nutrition and Metabolism. Jan 2006, 3(2):1743-707

Grassi D, et,al : Short-term administration of dark chocolate is followed by a significant increase in insulin sensitivity and a decrease in blood pressure in healthy persons. Am J Clin Nutr 2004;81:611– 4

I'm not trying to suggest that caffeine or flavonoid supplementation is a requirement; I'm confident that you can be perfectly healthy without them.  Rather, it seems like they could be an optimization, particularly for people who don't get enough vigorous exercise.

In addition to the Paleo diet, our evolutionary metabolic environment also included plenty of moving around, which decreases insulin resistance.  For those of us who are relatively sedentary, foods like caffeine and flavonoids may offset some of the negative effects of not getting enough exercise, by helping to maintain insulin sensitivity.

More scientific support for Paleo

Those looking for additional technical / scientific support for a Paleo-style diet might enjoy the following books:

Life Without Bread: How a Low-Carbohydrate Diet Can Save Your Life
By Christian Allan PhD and Wolfgang Lutz MD

Dangerous Grains: Why Gluten Cereal Grains may be Hazardous to Your Health
By James Braly MD and Ron Hoggan MA

[[MORE]]Both are rich with technical citations (as is Taubes, of course).

Then there’s the Hyperlipid blog: http://high-fat-nutrition.blogspot.com/, also written by a scientist.

One post that I found particularly enlightening:
http://high-fat-nutrition.blogspot.com/2009/03/cholesterol-within-nations-studies.html

It includes the graphs below (derived from published papers), which say that your relative risk of heart disease is much more strongly correlated to your HbA1c level than to total cholesterol.  How do you minimize HbA1c (glycated hemoglobin, which is caused by high levels of blood sugar)?  With a low-carb / paleo diet.