Understanding Nutrition 10th Edition
by Ellie Whitney, PhD, and Sharon Rady Rolfes, MS
Thomson Wadsworth, 2005
With over a million copies sold, Understanding Nutrition casts a major influence on dietitians and nutritionists and, consequently, on the current dictates of dietary recommendations. The authors assure their readers that their work is based on the best science available, and that only a Registered Dietitian (RD) can be relied upon for accurate nutrition information. It should be noted that an RD degree can be obtained by achieving a four-year degree in a related subject, and then passing an examination given by the American Dietetic Association.
Whitney and Rolfes intended to comprehensively cover all topics of nutrition, and they could have via Understanding Nutrition’s 990 big pages. Their writing is very clear, but contains internal inconsistencies. Many citations appear to support the authors’ (and ADA’s) positions. Kilocalories (kcal) are correctly used instead of calories. The authors provide advice for the “average” American for whom they have made tiny changes in intakes of many nutrients based on age, sex and pregnancy, but none for metabolic types, such as low-carbohydrate diets for people prone to diabetes, or special diets for those with most types of food allergies.
The authors make a serious omission of celiac and Crohn’s diseases and their causes, which are grain, gluten, and gliadin allergies, and which also lead to several types of cancers. This neglect must be related to the authors’ incessant promotion of whole grain foods, and carbohydrates in general, despite the fact that 10-50 percent of Americans suffer from grain allergies. The authors discuss high-fat intake as the purported cause of irritable bowel syndrome, while grains, damaged intestinal flora and stress are the more likely factors.
While “balanced diets” are lauded, the actual diets recommended are high in carbohydrates (300 grams per day, 60 percent of energy intake), tempered only to 50 percent for diabetics, despite extensive un-cited findings that serum glucose control, hyper- and hypoglycemia are uncontrollable with such diets. Type-2 diabetes is preventable and treatable with low-carbohydrate, high-fat diets, which are anathema to these authors. The authors’ fear of fat, especially animal fat, comes from their belief that fat is supposedly atherogenic, one of the most pervasive messages in this book, and one which ignores evidence of superlative cardiac health in groups such as the Inuit, Maasai, and long-term (up to fifty years) use of high-animal fat diets by physicians.
The Spanish Paradox (among others) was the result of observations that between 1964 and 1991, per capita bread consumption in Spain fell by 55 percent, rice by 35 percent, and potato by 53 percent while beef and full-cream milk consumption doubled, poultry tripled, and pork intake quadrupled. During this same period heart disease deaths fell by 25 percent in men and 34 percent in women; blood pressures and stroke deaths also dropped. The Spanish now live two years longer than Americans.
Between 1959 and 2004, researchers published at least fifty articles seeking to prove a connection between fat intake or serum cholesterol levels and “heart disease” (CVD) in which none could find a positive correlation.
Among the chemistry errors found in Understanding Nutrition is the claim that loss of an electron by a stable molecule always creates a free radical, implicated in atherogenicity and carcinogenicity (page 389). In some contexts, electron loss leads to formation of a positive and negative ion pair, not a free radical, which is commonly formed when a hydrogen atom with its electron is removed. However, this is exactly what happens with polyunsaturated fatty acids; they are more likely to form free radicals (and go rancid) than saturated or monounsaturated fats, making them less desirable.
The authors also ignore a well done study (Rose, 1965, British Medical Journal) that pitted animal fat against olive and corn oils. After two years, 75 percent of subjects consuming animal fats were free from major cardiac events, compared to 57 percent of those consuming olive oil, and 52 percent of those who consumed corn oil.
Cholesterol is such a bugaboo to Whitney and Rolfes that they describe not a single direct function of this vital nutrient in the body! Cell and organelle membrane illustrations show no cholesterol present, where, in fact, it is an essential structural component, as it also is in nerve synapses and other brain functions. The authors ignore the demonstrated association of low cholesterol levels with cancer, depression, violence, and all-cause mortality. Uffe Ravsnkov, MD, PhD, has analyzed many of the original studies and trials cited in Understanding Nutrition to try to find support for saturated fat or cholesterol’s alleged deadly role in heart disease, with absolutely no success (The Cholesterol Myths). The original sources provided either no evidence to support these claims or directly contradicted them.
Whitney and Rolfes even extol the Seven Countries Study of Ancel Keys, MD (p.174), long exposed as a fraud based on data suppression. In addition, the authors quote a publication of the National Heart, Lung and Blood Institute which claims that a 1 percent reduction of serum cholesterol level gives a 2 percent reduction in incidence of CVD (p.176), but a concurrent publication and many other studies have shown the opposite. In the elderly, those with higher cholesterol levels live the longest, as do those whose cholesterol levels do not drop on their own.
Understanding Nutrition strongly recommends dietary fiber to prevent both CVD and colon cancer, despite the authors’ admission that the research was contradictory (p. 124). A sixteen-year study on 89,000 women and a metaanalysis of seventeen studies showed no effect on CVD and 35-50 percent increases in colon cancer.
Salt limitation to less than six grams per day “to lower blood pressure” is advocated by the authors despite very persuasive evidence showing that when limiting salt to such an extent blood pressure will go down in only one-fifth of people, that it will go up in one-fifth, and that three-fifths will be almost unaffected by changing salt intake. Overall, in the gigantic Intersalt trial, there was little effect of salt on blood pressure, while increased potassium intake was hypotensive. In 2003, the Cochrane Collaboration agreed.
Physicians who ignore the recommendations of dietitians may be justified. Calls for courses in nutrition for physicians and other health providers, if based on books such as this, might not be worthwhile. Therefore, this book is not recommended, despite some valuable content.
The best single-volume (non-textbook) nutrition book that I know of is Barry Groves’s Trick and Treat: How “Healthy Eating” is Making Us Ill, London, England: Hammersmith Press, 2008. See my Amazon.com review for more details.
I have found over one hundred thirty questionable statements in Understanding Nutrition other than those noted above. For a complete list, with references to back up my positions, e-mail me at firstname.lastname@example.org.
This article appeared in Wise Traditions in Food, Farming and the Healing Arts, the quarterly magazine of the Weston A. Price Foundation, Fall 2009.