This page contains portions of press releases
concerning research by Dr. Siguel
Press release for the American Heart
Association meeting, Nov, 1994
Press release for the ISSFAL
meeting, June, 1995.
How do these findings
differ from NIH and USDA recommendations?
What sorts of questions
about USDA nutrition policies do these findings raise?
Press release describing exchange
of letters with the USDA published in The American Journal of Clinical
Nutrition, Dec94 and Sept95.
Press release for ISSFAL Meeting
International Society for the Study of Fatty Acids and Lipids (ISSFAL)
2nd International Congress in Washington, D.C.
June, 1995
Researchers identify EFAs as key nutrients that regulate TC/HDLC and recommend drastic changes in nutrition policy to prevent and treat cardiovascular disease
EFAs are excellent predictors of the TC/HDLC ratio. On average, subjects with low levels of EFAs had high levels of TC/HDLC, and subjects with high levels of EFAs had low levels of TC/HDLC. Furthermore, when subjects with high TC/HDLC eat more EFAs, TC/HDLC declines.
According to Edward Siguel, MD, PhD, the principal author of this research, blood levels of EFAs are a major nutritional factor regulating blood levels of TC/HDLC. EFA abnormalities are a cause of acquired (not genetic) atherosclerotic disease through their effects on membrane function.
The ratio of TC/HDLC in blood is one of the best factors for predicting the risk that a person will develop heart disease. It is one of the standards used to guide medical treatment. Lipoproteins, such as LDL, carry cholesterol, EFAs, and other nutrients to the body's cells. Dr. Siguel proposes that TC/HDLC reflects EFA status in the body because the particles (lipoproteins) that carry cholesterol are also the main carriers of EFAs. When levels of EFAs in LDL particles decline, the amount of LDL increases so that cells can get enough EFAs. According to Dr. Siguel and his colleague, Robert Lerman, MD, PhD, a deficiency of EFAs is the missing link relating nutrition to CAD (reported in Metabolism, August, 1994 and widely reported in the news media, including Time magazine and The New York Times).
The results reported by Dr. Siguel indicate that drastic changes should be made to current recommendations for the correction of abnormal cholesterol ratios. Instead of avoiding fat, people should eat foods rich in EFAs but low in calories. Using a nutritional blood test, doctors can determine what needs to be changed in the diet to reduce the TC/HDLC ratio by as much as 50%.
Such drastic changes are not possible with existing dietary or drug therapy. Current strategies to lower cholesterol frequently fail and vast sums of money are spent on nutritional programs and diets which may be ineffective (See New York Times 4/25/95, p. C13).
According to the American Heart Association (AHA), the recent Adult Treatment Panel (ATP II) report suggests that the Step I and II diets currently used by most physicians may lower cholesterol levels by about 8% to 14%. The AHA states that "[these] small average responses... may not be enough to achieve LDL cholesterol goals, and thus drug therapy may also be necessary."
The explosion in sales of cholesterol-lowering drugs underscores the lack of significant effectiveness of current dietary management for millions of Americans. The failure of current dietary treatment may cost each patient thousands of dollars per year, and the health-care system billions in the form of increased morbidity, expensive and invasive diagnoses, and surgery for CAD.
This research is based on the analyses of more than 500 subjects from the Framingham Heart Study. The relationship between EFAs and cholesterol had not been found previously, because the technology needed to accurately measure EFAs in human blood is highly complex and was only developed recently. The researchers used a method patented by Dr. Siguel, and described as "state-of-the-art" by NIH reviewers, to report as follows:
Levels of EFAs in the blood are highly
correlated with TC/HDLC. The relationship is similar for men and women,
suggesting that PUFA or EFA metabolism is a key mechanism that mediates
sex differences in TC/HDLC plasma levels. (PUFA = EFA + EFA derivatives = w3
+ w6 fatty acids.)
In individuals with low PUFA levels or
biochemical evidence of EFA insufficiency, treatment with diets consisting of
different fatty acid mixtures or oil supplements are indicated. Bringing the
fatty acid profiles of patients with high TC/HDLC closer to those of healthy
people should precede any decisions for drug therapy. The risks of such
treatment are minimal and the potential benefits highly significant.
Dr. Siguel's research leads to a new treatment for abnormal cholesterol ratios, a treatment that is substantially different from the one proposed by the AHA and NIH. The NIH recommends that people decrease their intake of SFAs, and increase their intake of both carbohydrates and MUFAs. Dr. Siguel proposes that people achieve ideal weight by reducing caloric intake from all sources. He also suggestss that people eat EFAs as needed to bring their EFA blood profile closer to that of healthy subjects.
Differences with NIH and USDA recommendations
In NIH publication No. 93-3095, the Adult Treatment Panel II (Panel II) states that "carbohydrates can be substituted isocalorically for fat, especially saturated fat." (page II-6). The Panel II also recommends that both Step I and Step II diets include up to 15% of fat from MUFAs, an increase over the amounts many people currently eat.
As shown in the study by Drs. Siguel and Lerman (Metabolism, August, 1994), plasma MUFA levels are primarily determined by plasma PUFA levels. Furthermore, Dr. Siguel's research has shown that MUFA plasma levels (both % and concentrations) are highly positively correlated with TC/HDLC. Thus, a long term increase of dietary MUFA intake will likely have an effect similar to increasing saturated fat, namely an increase in TC/HDLC. The Panel II makes no specific recommendations about the need for EFAs, the ratio of w3/w6, or the need for EFA derivatives vs. precursors.
According to Dr. Siguel, people should be concerned primarily with total calories (achieving ideal weight) and calories from PUFA to achieve ideal w3/w6 ratios. The amount of PUFAs to eat per day depends on the number of cells in the body. In contrast to AHA recommendations, Dr. Siguel states that people should not reduce their EFA intakes when they eat fewer calories. Eating the appropriate amount and mixture of EFA-rich foods will correct EFA abnormalities and usually decrease TC/HDLC.
Dr. Siguel recommends that people eat fewer calories from SFAs, MUFAs, and carbohydrates, until they achieve ideal weight. Individuals who consistently replace most fat with carbohydrates or those on low-calorie diets who strictly follow the USDA Food Pyramid may become deficient in EFAs. Although very low-fat diets may be safely prescribed to overweight individuals who have large reserves of EFAs in their bodies, Drs. Siguel and Lerman have stated that very low-fat diets, deprived of EFAs, may be counterproductive for many patients, particularly those who are not losing weight. For people who do not eat sufficient EFAs, nor have enough stored in their bodies, the government's dietary recommendations are ineffective. (See Am. J. of Clinical Nutrition, December, 1994 letter by Drs. Siguel and Lerman pertaining to the USDA Food Pyramid).
"I have spoken with many patients and physicians with elevated TC/HDLC levels who told me that those ratios increased on low-fat diets," states Dr. Siguel. "Based on my experience analyzing the blood of hundreds of patients and research subjects, low EFA blood levels are quite common" adds Dr. Siguel, who recently published a study which evaluated 200 adult subjects and found that EFA abnormalities are prevalent in more than 25% of the adult population. (Comprehensive Therapy, 1994; 20(9):500-510, Nutrition issue). "Whether or not millions of Americans are deficient in EFAs could be determined through studies that analyze the blood of young and old subjects," continues Dr. Siguel. "Unfortunately, despite the fact that the need for EFAs has been known for more than 30 years, patients are unaware that they need to eat EFAs," he said. Instead, the consumer is encouraged to eat artificial foods deprived of EFAs.
These findings
raise many questions that policy-makers should answer. These questions ought to
concern food manufacturers and health practitioners.
Physicians warn people about the dangers of tobacco smoking, which many know anyway. Should we not warn people about the dangers of low EFAs? Should the government require food companies to identify the amounts of w3 and w6 fatty acids in foods? Should we inform consumers about which foods contain and which do not contain EFAs? Should physicians inform patients that they are at risk for cardiovascular disease and other health problems if they have low levels of EFAs in their blood? Should we let people consume foods low in EFAs, even if these people may cause permanent harm to their bodies?
Because EFAs are essential, Dr. Siguel emphasizes that patients with low blood levels of EFAs should not follow very low-fat diets devoid of EFAs. Instead, they should eat diets to correct their fatty acid abnormalities. The changes recommended by Dr. Siguel should lead to substantial revisions in the way abnormal cholesterol ratios are treated today. They offer a practical alternative to save billions of dollars in health care costs while improving quality of life and life expectancy.
Should the
USDA's Food Pyramid be changed to de-emphasize low fat processed foods and
include more natural foods with essential fatty acids?
September, 1995
Are Low Fat Diets Dangerous to Your Health? Should you supplement your Low Fat Diet with oils rich in EFAs? Should we change US nutrition policy?
Research has shown that many Americans have insufficient amounts of EFAs in their blood. Low fat diets are, by design, low in EFAs and can deplete a person of these essential nutrients. In the American Journal of Clinical Nutrition (December, 1994), Drs. Siguel and Lerman stated that "current U.S. Department of Agriculture (USDA) nutritional recommendations represented by the 'pyramid'... are misleading" (because they encourage people to eat low fat foods, pastas, and grains without EFAs).
In the September, 1995, issue of the American Journal of Clinical Nutrition, the USDA replies and explains its position regarding the Food Pyramid and current nutrition recommendations. The USDA speaks about the need for EFAs and whether people should add oils rich in EFAs to their foods, particularly low fat foods.
In a reply in the same issue, Drs. Siguel and Lerman state that the implicit and explicit assumptions and citations in the USDA's Pyramid justification are scientifically incorrect, as they are based on obsolete recommendations [for EFA needs]. See USDAFAT2
Drs. Siguel and Lerman add that it is irrelevant that the USDA believes that Americans eat enough EFAs or that EFA deficiency is not prevalent. What matters are data from appropriate blood tests. Dr. Siguel has analyzed the fatty acid profiles of 500+ adults from the Framingham Heart Study. More than 20% had biochemical evidence of deficiency, and at least 5% had severe deficiencies of w3 and w6 are essential fatty acids. Dr. Siguel found that EFA abnormalities are the most significant nutritional factor in elevated TC/HDLC [one of the best biochemical markers of risk for heart disease].
"Our clinical experience and research data indicate that the USDA nutrition recommendations, coupled with misleading food labels, are a major contributory factor to cardiovascular disease. Unless drastic changes are made in nutrition policy to emphasize the need for EFAs, we are afraid that current policies may increase morbidity and mortality." [in plain words, money would be saved and health improved by revamping current nutrition policies]. Please see the complete letters in The American Journal of Clinical Nutrition, available at medical libraries.
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© 1998 Edward N. Siguel. All rights reserved |
modified 9/12/98 |