High-Grain Diet May Increase Risk of Cardiovascular Disease

American Journal Clinical Nutrition January 2003 77: 43-50

When humans consume more carbohydrates than can be stored, the excess carbohydrate energy is converted to fat by the liver. This process may maintain blood sugar control and prevent diabetes in the short-term, however it may also increase triglyceride concentrations, which may increase the risk of cardiovascular disease.

In the last decade, researchers established that fat production by the liver varies depending on dietary habits and health status.

The typical Western diet has a high fat content, which means that only a limited amount of carbohydrates are available for liver fat production, and liver fat production tends to be very low among individuals who eat this type of diet. However, when too many carbohydrates were consumed, both liver fat and sugar production were increased.

A very low-fat (10 percent of energy) and very high-carbohydrate (75 percent of energy) diet also leads to increased liver fat production, with the increase being even more pronounced when more than half of the carbohydrate was consumed as simple sugars. This points to the importance of carbohydrate quality, as another study using 68 percent of energy from complex carbohydrate resulted in minimal liver fat production.

However, it was found that obese individuals with high insulin levels who consume a high-fat (40 percent of energy) diet had a liver fat production rate three to four times higher than that of lean individuals with normal insulin levels. But, both normal and high insulin groups had lower liver fat production on the high-fat diet than on a low-fat, high-carbohydrate diet.

Moreover, the low-fat, high-carbohydrate diet caused an increase in triglyceride concentrations, a risk factor for coronary heart disease, which was associated with the liver fat production in both normal and high-insulin individuals.

Researchers concluded that the low-fat, high-carbohydrate diet might not be ideal, as it can induce liver fat production and insulin resistance. This is especially true when most of the carbohydrate is in the form of simple sugars.

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1: Am J Clin Nutr 2003 Jan;77(1):43-50

Hepatic de novo lipogenesis in normoinsulinemic and hyperinsulinemic subjects consuming high-fat, low-carbohydrate and low-fat, high-carbohydrate isoenergetic diets.

Schwarz JM, Linfoot P, Dare D, Aghajanian K.

Department of Nutritional Sciences and Toxicology, University of California, Berkeley (J-MS and KA), and the Department of Medicine, University of California, San Francisco (J-MS, PL, and DD).

BACKGROUND: Hypertriglyceridemia is associated with increased risk of cardiovascular disease. Until recently, the importance of hepatic de novo lipogenesis (DNL) in contributing to hypertriglyceridemia was difficult to assess because of methodologic limitations. OBJECTIVE: We evaluated the extent of the contribution by DNL to different conditions associated with hypertriglyceridemia. DESIGN: After 5 d of an isoenergetic high-fat, low-carbohydrate diet, fasting DNL was measured in normoinsulinemic (</= 85 pmol/L) lean (n = 9) and obese (n = 6) and hyperinsulinemic (>/= 115 pmol/L) obese (n = 8) subjects. Fasting DNL was measured after a low-fat, high-carbohydrate diet in normoinsulinemic lean (n = 5) and hyperinsulinemic obese (n = 5) subjects. Mass isotopomer distribution analysis was used to measure the fraction of newly synthesized fatty acids in VLDL-triacylglycerol. RESULTS: With the high-fat, low-carbohydrate diet, hyperinsulinemic obese subjects had a 3.7-5.3-fold higher fractional DNL (8.5 +/- 0.7%) than did normoinsulinemic lean (1.6 +/- 0.5%) or obese (2.3 +/- 0.3%) subjects. With the low-fat, high-carbohydrate diet, normoinsulinemic lean and hyperinsulinemic obese subjects had similarly high fractional DNL (13 +/- 5.1% and 12.8 +/- 1.4%, respectively). Compared with baseline, consumption of the high-fat, low-carbohydrate diet did not affect triacylglycerol concentrations. However, after the low-fat, high-carbohydrate diet, triacylglycerols increased significantly and DNL was 5-6-fold higher than in normoinsulinemic subjects consuming a high-fat diet. The increase in triacylglycerol after the low-fat, high-carbohydrate diet was correlated with fractional DNL (P < 0.01), indicating that subjects with high DNL had the greatest increase in triacylglycerols. CONCLUSIONS: These results support the concept that both hyperinsulinemia and a low-fat diet increase DNL, and that DNL contributes to hypertriglyceridemia.

PMID: 12499321 [PubMed - in process]

http://www.ncbi.nlm.nih.gov/entrez/...1&dopt=Abstract
http://www.mercola.com/2003/jan/8/high_grain_diet.htm

"Researchers concluded that the low-fat, high-carbohydrate diet might not be ideal, as it can induce liver fat production and insulin resistance. This is especially true when most of the carbohydrate is in the form of simple sugars."

Mmm-hmm. Now let's see how many papers and other media sources turn this study into a story. (Call me a pessimist, but I bet 'zero.')

"another study using 68 percent of energy from complex carbohydrate resulted in minimal liver fat production."

Leaders in the Despised Enemy Camp (e.g., Ornish) proclaim this very thing. They acknowledge that the white flour/white sugar approach is grossly unhealthy and that high quality complex carbohydrates from whole grains, legumes, etc., are essential both to cardio and overall health. The above quote actually *supports* their conclusions.

The only reason I bring this up is that, as one of those rare birds, a vegetarian following a low-carb plan, I've read numerous attacks on high-carb vegetarian diets. The attacks usually draw the same erroneous contrast: i.e., between a low-carb/high-fat regimen, and a high-*simple*-carb regimen. Well, duh, of course the simple carb (sugar/white flour) regimen is unhealthy. But that's not what most vegetarians follow (if you'll permit a gross generalization). They are far more likely to consume the "68 percent of energy from complex carbohydrate" and thereby not suffer the ill effects described in this article.

As someone with feet planted in both camps, I try to keep an open mind. I'm troubled by the distorting headline in this article (High-Grain Diet May Increase Risk of Cardiovascular Disease--nowhere in the article does the word "grain" actually appear. Who came up with this headline? Well, what do you know, some guy with low-carb product to sell. Hmmmmm.)

In short, I see nothing in this article which says that my beloved brown rice is deadly. Sure we can argue glycemic indexes and whatnot, but what I'm really trying to communicate is that pre-conceived notions (Low Carb Rules! Low-fat Rules!) can get in the way of objective analysis and cause us to admit some information ("Researchers concluded that the low-fat, high-carbohydrate diet might not be ideal, as it can induce liver fat production and insulin resistance") while filtering out other information inconsistent with those notions ("another study using 68 percent of energy from complex carbohydrate resulted in minimal liver fat production.")

P.S. I'm losing weight like a nuke victim on this low-carb thang. Lord knows though, I would never make it a permanent diet. When I reach my desired weight, I will return to a plan which includes plenty of whole grains, but excludes the garbage carbs which got me into trouble in the first place.

Welcome aboard Van_Delay,

There is one group of vegetarian that we are strongly against, and it has nothing to do with vegetables or being vegetarian It's the PCRM/Ornish combo. The reasons can be found throughout many threads here, and it it focuses on them not being vegetarians, but anti-meat and anti-fat propaganda machines promoting a truely unhealthy combination, and they take it as a religous war of zealots.

As to the news and research being tracked on this forum,, we try to keep informed on all points of views, and you will find references to both, pro low-carb, and anti lo-carb opinions and studies.

Here's what got my attention to this study:



Yes, simple sugars are bad, and complex-, low-glycemic carrbs are better. The basic premise of all low-carb plans is less carbs, not zero carbs. So if some one tells me that vegetables are good, I won't be defensive, and most likely, I'm consuming more veggies than any of these Ornish/PCRM gurus.!

As for complex carbs, all low-carb diets allow it and even insist on it, in different amounts based on the theory of each of the corresponding low-carb plan, and we're not here as a no-carb support group, we're a low-carb support group.

Congrats on your loss

Wa'il