Fructose, weight gain, and the insulin resistance syndrome

American Journal of Clinical Nutrition, Vol. 76, No. 5, 911-922, November 2002
© 2002 American Society for Clinical Nutrition

Sharon S Elliott, Nancy L Keim, Judith S Stern, Karen Teff and Peter J Havel

From the Department of Nutrition, University of California, Davis (SSE, JSS, and PJH); the US Department of Agriculture Western Human Nutrition Research Center, Davis, CA (NLK); and the Monell Chemical Senses Institute and the University of Pennsylvania, Philadelphia (KT).

This review explores whether fructose consumption might be a contributing factor to the development of obesity and the accompanying metabolic abnormalities observed in the insulin resistance syndrome. The per capita disappearance data for fructose from the combined consumption of sucrose and high-fructose corn syrup have increased by 26%, from 64 g/d in 1970 to 81 g/d in 1997. Both plasma insulin and leptin act in the central nervous system in the long-term regulation of energy homeostasis. Because fructose does not stimulate insulin secretion from pancreatic ß cells, the consumption of foods and beverages containing fructose produces smaller postprandial insulin excursions than does consumption of glucose-containing carbohydrate. Because leptin production is regulated by insulin responses to meals, fructose consumption also reduces circulating leptin concentrations. The combined effects of lowered circulating leptin and insulin in individuals who consume diets that are high in dietary fructose could therefore increase the likelihood of weight gain and its associated metabolic sequelae. In addition, fructose, compared with glucose, is preferentially metabolized to lipid in the liver. Fructose consumption induces insulin resistance, impaired glucose tolerance, hyperinsulinemia, hypertriacylglycerolemia, and hypertension in animal models. The data in humans are less clear. Although there are existing data on the metabolic and endocrine effects of dietary fructose that suggest that increased consumption of fructose may be detrimental in terms of body weight and adiposity and the metabolic indexes associated with the insulin resistance syndrome, much more research is needed to fully understand the metabolic effect of dietary fructose in humans.

Fruit: Are you missing it?

For most Low-carbers, the answer to the above question is “Oh golly gosh yes!” Me, I never was a “fruit fan”, so when I started LCing in 1999, it was one thing I never missed.

However, over 3 1/2 years on, and my taste buds have adapted to my lowered sweetness diet and I now enjoy, in moderation of course, many fruits that I thought were too bland, sour, or tart.

As a general rule, a fruit’s sugar content is governed by when the fruit is naturally produced by the plant. The amount of sun the plant gets controls the sugar content. (See Table 1)

Full article: Low Carb in the UK

Sweet and sour

Fructose is often given a clean bill of health, but Dr John Briffa argues that our trust may be misplaced

Sunday August 24, 2003
The Observer

"Nutritional scientists tell us that fructose, the principal sugar found in fruit, does not inflate levels of sugar or insulin in the system. Its seemingly benign effects mean that fructose has traditionally enjoyed a somewhat sugar-coated reputation."

Full article: Observer Magazine

Carbohydrates and Immune Function

"Based on these studies, any person who eats largely carbohydrate-based meals, particularly those containing sugars, and snacks with small carbohydrate-based meals spread throughout the day -- as the latest advice suggests we should -- could lose up to half their immunity to disease for much of the waking day. "

Full article: Second Opinions - Barry Groves, PhD

High carbohydrate diet implicated in pancreatic cancer

From the British Medical Journal

Full article: BMJ

Effects of dietary fructose on plasma lipids

Effects of dietary fructose on plasma lipids in healthy subjects1,2,3

John P Bantle, Susan K Raatz, William Thomas and Angeliki Georgopoulos

1 From the Department of Medicine, the General Clinical Research Center, the Division of Biostatistics, and the School of Public Health, the University of Minnesota, Minneapolis, and the Veterans Administration Medical Center, Minneapolis.

Background: About 9% of average dietary energy intake in the United States comes from fructose. Such a high consumption raises concern about the metabolic effects of this sugar.

Objective: The objective of this study was to determine the effect of dietary fructose on plasma lipids.

Design: The study was conducted in the General Clinical Research Center at Fairview-University of Minnesota Medical Center. The participants were 24 healthy adult volunteers (12 men and 12 women; 6 of each sex were aged <40 y and 6 of each sex were aged 40 y). All subjects received 2 isoenergetic study diets assigned by using a randomized, balanced crossover design. One diet provided 17% of energy as fructose. The other diet was sweetened with glucose and was nearly devoid of fructose. Each diet was fed for 6 wk. Both diets were composed of common foods and contained nearly identical amounts of carbohydrate, protein, fat, fiber, cholesterol, and saturated, monounsaturated, and polyunsaturated fatty acids. All meals were prepared in the metabolic kitchen of the General Clinical Research Center.

Results: The responses to the study diets differed by sex. In men, the fructose diet produced significantly higher fasting, postprandial, and daylong plasma triacylglycerol concentrations than did the glucose diet. The daylong plasma triacylglycerol concentration after 6 wk of the fructose diet was 32% greater in men than the corresponding concentration during the glucose diet (P < 0.001). The fructose diet had no significant effect on fasting or postprandial plasma triacylglycerol concentrations in women. The fructose diet also had no persistent effect on fasting plasma cholesterol, HDL cholesterol, or LDL cholesterol in either men or women.

Conclusions: Dietary fructose was associated with increased fasting and postprandial plasma triacylglycerol concentrations in men. Diets high in added fructose may be undesirable, particularly for men. Glucose may be a suitable replacement sugar.

Key Words: Dietary fructose • dietary glucose • healthy adults • plasma lipids • plasma glucose • serum insulin

American Journal of Clinical Nutrition, Vol. 72, No. 5, 1128-1134, November 2000 © 2000 American Society for Clinical Nutrition

Source: http://www.ajcn.org/cgi/content/abstract/72/5/1128