Saturday, August 16, 2014

The Nutrition Debate #236: Inflammation and the Low Carb Diet

Low-carb dieter and popular type 2 blogger David Mendosa recently wrote an article about chronic systemic inflammation and low-carb dieting inHealth Central. He referred to another inflammation piece he wrote in Health Central in 2009. They were both interesting, but what really caught my attention was a link Mendosa provided to a PubMed abstract titled, “Advice to follow a low-carbohydrate diet has a favourable impact on low-grade inflammation in type 2 diabetes compared with advice to follow a low-fat diet.” The full text is available from the Annals of Medicine here.

Mendosa begins his 2009 piece with this: “More and more research pinpoints inflammation as a root cause of type 2 diabetes.” He added, “Type 2 diabetes generally results from the combination of impaired beta cell function and insulin resistance acting on susceptible genes.” In his 2014 piece Mendosa relates these two disparate phenomena with a quote from Dr. Richard K. Bernstein, the pied piper of very low carb dieting and blood glucose monitoring to manage diabetes.

Mendosa, quoting Bernstein from his encyclopedic book Diabetes Solution:

“To simplify somewhat, inheritance plus inflammation plus fat in the blood feeding the liver causes insulin resistance, which causes elevated serum insulin levels, which cause the fat cells to build even more abdominal fat, which raises triglycerides in the liver’s blood supply and enhances inflammation, which causes insulin levels to increase because of increased resistance to insulin.”

If that vicious cycle is too “geeky” and confusing for you – it is to me, then this new Swedish study – the “Advice to follow…” link above – is not. The headline says it simply: A low-carb diet has a favorable impact on low-grade inflammation in type 2 diabetes compared with a low–fat diet.

The Abstract’s BACKGROUND sets up the study: “Inflammation may play an important role in type 2 diabetes. It has been proposed that dietary strategies can modulate inflammatory activity.”

The low-carb diet used in the study was 20% carbohydrates. That’s 100 grams of carbohydrate a day on a 2,000 calorie a day eating plan. The low-fat diet was 55-60% carbohydrate, or 275 to 300 grams of carbohydrate a day. This is the amount, if you didn’t know, that the Dietary Guidelines for Americans recommends and the amount on which the Nutrition Facts panel of packaged and processed foods is based. That’s stunning to most people. If you don’t believe me, check it out for yourself.

In “my book,” 100 grams of carbohydrate a day is very high-end low-carb. Perhaps it was chosen as the “low-carb” amount for the study so as to be seen as an “achievable” amount by people just starting out in the low-carb Way of Eating. It is certainly achievable by anyone who gives it a good faith try. But, it must be said that cutting carbohydrate consumption by two-thirds (from 300g/day) is no small feat. It is undoubtedly a sufficient reduction for the majority of people who are not already diagnosed type 2s. It would make management with medications for diagnosed type 2s so much easier. And it may make reversal of pre-diabetes possible for people whose glucose tolerance is not already too badly impaired.

So, what did this randomized, real-world study reveal? RESULTS: “Both the low fat diet and low carb diets led to similar reductions in body weight, while beneficial effects on glycemic control were observed in the low carb group only.” In addition, using various clinical laboratory measures, after 6 months, inflammatory markers “were significantly lower in the low- carb group than in the low-fat group.”

Table IV from the full-text of the study, showing data for all the inflammation markers tested, is reproduced here. Note the CRP of the low-fat dieters actually increased 18% from1.41 to 1.67mg/L, while the CRP of the low carb dieters decreased 22% from 1.12 to 0.87mg/L.

CONCLUSION: “To conclude, advice to follow a low carb diet or a low fat diet had similar effects on weight reduction while effects on inflammation differed. Only the low carb diet was found significantly to improve the subclinical inflammatory state in type 2 diabetes.”
Wikipedia tells us that CRP has a half life of 48 hours, so the anti-inflammatory effects of a diet change can begin quickly.  Have your CRP levels been checked?

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