Triglyceride levels, which play a large role in both atherosclerotic risk and metabolic health, are highly responsive to decreases in dietary sugar intake and saturated and trans fat intake, along with increases in omega-3 acid intake and exercise, according to a scientific statement from the American Heart Association.
"What’s new is that we point out that triglycerides might be considered a marker for metabolic health," said Dr. Neil J. Stone of Northwestern University, Chicago, vice chair of the statement’s writing group, in an interview. "If you have a country where you’re seeing more obesity and more diabetes, it becomes important for people to start asking themselves ‘are there signs that I should be doing something different?’ and this is one," he said.
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Fructose in excess of 100 g/day, and possibly in excess of 50 g/day, has been associated with raised triglyceride levels. A typical can of cola or lemon-lime soda contains more than 20 grams of fructose.
The scientific advisory, published online April 18 in the journal Circulation and citing some 528 sources, was not presented as a clinical guideline so much as a distillation of 30 years worth of evidence on the complex relationship among lifestyle factors, triglycerides, and cardiovascular and metabolic health (Circulation 2011 [doi:10.1161/ CIR.0b013e3182160726]).
However, the statement’s authors, led by Dr. Michael Miller, director of the Center for Preventive Cardiology at the University of Maryland, Baltimore, included a number of recommendations on diagnosing and treating hypertriglyceridemia, focusing on dietary and lifestyle changes.
The statement emphasizes the "increasingly crucial role" of triglycerides in the evaluation and management of cardiovascular disease, and the importance of diet – including consumption of sugars common in beverages – in contributing to unhealthy triglyceride levels.
Reductions of 50% or more are achievable without the use of medication – indeed medication is not a widely accepted strategy for reducing triglycerides except among people with extremely high values of greater than 500 mg/dL. "The subject of medication and triglycerides is still lacking crucial clinical trial evidence," Dr. Miller and colleagues wrote in their analysis, noting that certain medications, including hormonal treatments, can also contribute to elevated triglycerides.
About a third of American adults have elevated triglyceride levels, which are defined as fasting triglyceride of 150 mg/dL or higher. The authors recommended that optimal fasting triglyceride levels now be defined as 100 mg/dL – and that clinicians screen initially for nonfasting triglyceride, defining normal at below 200 mg/dL. People with higher nonfasting levels may then be further screened for fasting triglyceride.
The new dietary recommendations include restricting added dietary sugar to 5%-10% percent of calories consumed. In support of this, the authors cited a study of 6,113 U.S. adults showing that the lowest triglyceride levels were observed when added sugar represented less than 10% of total energy, and that higher triglyceride levels corresponded with added sugar accounting for a greater proportion of energy intake (JAMA 2010;303:1490-7).
The authors singled out fructose, a type of dietary sugar increasingly common in processed foods and soft drinks, as particularly problematic. Fructose in excess of 100 g/day, and possibly in excess of 50 g/day, has been associated with raised triglyceride levels. A typical can of cola or lemon-lime soda contains more than 20 grams of fructose, the authors noted.
Dr. Miller and his colleagues advocated weight loss of 5%-10% of body weight, which is associated with a 20% reduction in triglycerides, and regular aerobic exercise, to reduce triglyceride levels closer to optimal.
They also promoted increasing dietary fiber, keeping saturated fat below 7% of calories, eliminating trans fat from the diet, and increasing omega-3 polyunsaturated fatty acid consumption in the form of marine fish, though the authors said more research was needed to determine whether supplementing with fish-oil capsules provided equivalent benefits. Complete abstinence from alcohol was also recommended for people with very high triglycerides.
"Overall, optimization of nutrition-related practices can result in a marked triglyceride-lowering effect that ranges between 20% and 50%," they concluded.
Funding for the scientific advisory statement was provided by the American Heart Association. Dr. Miller declared no conflicts of interest affecting the drafting of the statement. However, Dr. Stone and the report’s third author, Dr. Christie Ballantyne of Baylor College of Medicine in Houston, disclosed support from pharmaceutical industry sources. Other coauthors and some reviewers disclosed additional support from pharmaceutical and agricultural firms.