Animal Based Low Carb Diet Boosts Death Risk
Animal-based low carb diet boosts death risk
Not all fats and proteins are created equal when it comes to their nutrition values. Low carbohydrate diets may either boost or reduce premature death risk, depending upon the source of fat and protein included in the diet, according to a new study.
The study, led by Teresa T. Fung, ScD and colleagues from Harvard School of Public Health and the National University of Singapore, found that a low-carbohydrate diet can boost death risk if it is based on animal fat and protein.
The controversial Atkins diet is based on high animal fat while the South Beach diet is based on high animal protein. The U.S. government dietary guidelines recommend that no more than 30 percent of daily calorie intake should be made up of fat, most of which is in fact derived from animals.
Conversely, the same study found that a low-carbohydrate diet based on fat and protein derived from plants can actually reduce risk of premature death.
For the study, the researchers looked at data from two prospective cohort studies, the Nurses' Health Study of 85,168 women aged 34 to 59 years and the Health Professionals' Follow-up Study of 44,548 men aged 40 to 75 years in 1986.
Women were followed for their dietary habits from 1980 through 2006; men were followed from 1986 through 2008. During the follow-up, 12,555 women and 8678 men died mostly from cardiovascular and cancer related causes.
Overall, low-carbohydrate diets were associated with a moderate increased risk of death in a pooled analysis. To be exact, the increase in the risk was 12 percent..
Those who consumed the highest amounts of animal fat and protein in their low carbohydrate diest were 23 percent more likely to die from all-causes, 14 percent more likely to die from cardiovascular causes, and 28 percent more likely to die from cancer, compared to those who consumed the lowest amounts of animal fat and protein.
In contrast, those whose low carbohydrate diet had the highest amounts of fat and protein from plants were 20 percent less likely to die from all causes and 23 percent less likely to die from cardiovascular causes.
The authors of the study cautioned that there are some limitations. The dietary information collected from study participants was not 100 percent accurate; additionally, participants were not representative of the general population, meaning that the study results may not be applicable to the population at large.
The study was sponsored by the National Institutes of Health.
Similarly, Dr. Colin T. Campbell, distinguished nutrition professor at Cornell University, conducted a study in China and found that plant-based diets were linked with a lower risk of so-called affluent diseases such as diabetes, heart disease and cancer.
He says in his book, China Study, that in certain counties where animal foods were rarely consumed, chronic diseases like cancer were rarely seen.
Dr. Campbell's laboratory studies revealed that people who ate animal proteins such as milk proteins were more vulnerable to the damage induced by aflatoxin B, which induces liver cancer. But in animals fed soy proteins, aflatoxin B had no effect on the animals' health.
by David Liu, Editing by Rachel Stockton
Editor's note: We received the following from
The press release is cited below:
Conclusions Flawed in Comparison of Animal-and Plant-Based 'Low-Carbohydrate' Diets
'LOW-CARB' COMPONENT BEARS NO RESEMBLANCE TO ATKINS DIET
DENVER, Sept. 6 /PRNewswire/ -- Headlines make news, but don't read too much into current headlines about a recent study titled "Low-Carbohydrate Diets and All-Cause and Cause-Specific Mortality," published in the September 7, 2010, issue ofAnnals of Internal Medicine. Although the headlines may say the study suggests that long-term adherence to a low-carb diet based heavily on animal protein may reduce lifespan, Dr. Funga, who was the lead author of the study, says that her research "is not representative of popular low-carb eating plans." She goes on to note that her study "is observational and based on a limited pool of health professionals rather than a large-scale, clinical trial based on a varied population. Other issues in the design of the study, such as depending on food frequency questionnaires, impact its conclusions." So why all the fuss? Headlines make news but headlines can be misleading; and that's why Atkins wants to clarify study conclusions and correct any misperception.
- The "Low-Carb" Diet Is Not Representative of Atkins. The so-called "low-carb" diet referenced in Dr. Funga's research is not representative of Atkins. In the journal's editorial, Drs. Yancy, Maciejewski, and Schulman, of Duke University Medical Center commented on Dr. Funga's study. They wrote, "The participants in the highest decile of low-carbohydrate diet score (that is, those eating the least amount of carbohydrate) actually had a moderately high carbohydrate intake."
- The Protocol Is Not Atkins. Dr. Jeffrey Volek, associate professor at the University of Connecticut, notes that, "In respect to the Atkins Diet, it should be emphasized that using these data as an indictment of the diet as being unhealthy is inappropriate. From the data presented, the cohort with the lowest carbohydrate intake had a median carbohydrate intake (percentage of energy) of 35 percent for men and 37 percent for women. This is nowhere close to the level of carbohydrate restriction in any phase of the Atkins Diet."
- Low-Carb Diets Work. Major clinical research has demonstrated the health benefits of low-carb diets. Dr. Eric Westman, also of Duke University Medical Center, noted that, "The randomized controlled trials have repeatedly sided with, not against, low-carbohydrate diets. The latest study, published in Circulation 2010 by Dr. Shai and colleagues, showed that the low-carbohydrate diet (with animal sources of protein) led to reduction in carotid artery thickness over a two year period."
- As the editorial authors stated, several clinical trials in the past 10 years have demonstrated that a low-carbohydrate, high-fat, high-protein diet is at least as effective as a calorie-restricted, high carbohydrate, low-fat diet for weight loss and improvement of heart health risk factors. A recently published study of two years duration found that a low-carbohydrate diet had better HDL ("good") cholesterol and triglyceride results than did a low-fat diet.
- Current Study Limitations. According to Dr. Westman, "This study is observational so it measures associations and cannot prove causation. Moreover, the association found was extremely weak." Dr. Volek added, "What strikes me about this study is the assumption by the authors that that a massive number of subjects overcomes the well known limitations associated with using food frequency questionnaires (FFQ). Even if we assume some level of accuracy in assessing carbohydrate and overall nutrient intake by FFQ, the authors only examined food intake once: at the start of the 20-plus-year study. If a person changed his diet at any point during the two-decade study it would not be reflected in the analysis."
- Atkins also takes issue with how the study determined which low-carb diets were vegetable-protein based and which were animal-protein based. As noted by the journal's editorial authors, "It turns out that participants in the highest decile of the vegetable score consumed similar amounts of fat and protein from animal sources as did participants in the upper deciles of the animal source." Continued the editorial authors, "Despite lay press representation to the contrary, low-carbohydrate diets are fairly rich in vegetables, particularly after the early restrictive phase of these diets." This is evident in the Atkins approach which emphasizes the consumption of low-glycemic fruits and vegetables and vegetarian proteins such as tofu, in addition to animal proteins.
The Bottom Line
Dr. Funga's work may be thought provoking and newsworthy, but she acknowledges that nothing in her research takes away from recent clinical research and findings about the health benefits associated with low-carb diets. She acknowledges many of the weaknesses and limitations associated with long-term observational studies, and the difficulties conducting them. In the last ten years, peer-reviewed journals have published more than 60 studies investigating low-carb diets, many of them based on Atkins protocols. All demonstrate positive results in terms of weight loss, as well as improvements in lipid profiles, reduced inflammation and better blood sugar control. In contrast, a single study, with significant limitations, suggests caution about the sources of protein.
About Atkins Nutritionals, Inc.
Atkins Nutritionals, Inc., is a leading player in the $2.4 billion dollar weight-control nutrition category, and offers a powerful lifetime approach to weight loss and weight management. The Atkins Diet™, also known as the Atkins Nutritional Approach, focuses on a healthy diet with reduced levels of refined carbohydrates and added sugars and encourages the consumption of protein, fiber, fruits, vegetables and good fats. Backed by research and consumer success stories, this approach allows the body to burn more fat and work more efficiently while helping individuals feel less hungry, more satisfied and more energetic.
Atkins Nutritionals, Inc., manufactures and sells a variety of nutrition bars, foods and shakes designed around the nutritional principles of the Atkins Diet. Atkins' four product lines -- Advantage®, Day Break™, Endulge™ and Cuisine™ -- appeal to a broad audience of men and women who want to achieve their weight management goals and enjoy a healthier lifestyle. Atkins products are available in more than 30,000 locations throughout the U.S. and internationally. For more information, visit atkins.com.
SOURCE Atkins Nutritionals, Inc.