August 2014

Diet in Reducing Cholesterol

The Role of Diet in Reducing Cholesterol
in Heart Disease and Stroke

Can diet lower cholesterol and risk of heart disease? The American Heart Association counsels people who are at risk for CAD to start on a diet which reduces both total fats and saturated fats as soon as is possible. Along with this they generally tell people to stop smoking, and treat high blood pressure if it is present.

In one study a group of middle-aged Norwegian smokers with very high cholesterol levels (mean 320 mg/dL) and very high fat consumption (44% calories) was started on such a program. Cholesterol was lowered by some 13% across the board. When smoking was also reduced or stopped CAD incidence was lowered by 47%.

When this study was tried in other areas much smaller, changes in the range of 0-5% reductions in cholesterol were noted. In these studies the rate of CAD was not significantly lowered. It has been theorized that the difference between the Norwegian study and the others was caused by ineffective counseling and follow-up, lower baseline cholesterol levels at the beginning of these other studies or adverse effects of other therapies.

In possibly the most systematic study of dietary counseling in adults, a group of 6,000 men (with mean cholesterol levels of 253 mg/dL) was studied for 10 weeks. The men were seen weekly in group sessions and periodic individual counseling was provided over a period of some six years. In this study the average cholesterol declined by 5% in men receiving counseling, however, the in the control group which had no counseling blood cholesterol levels dropped by 2%. Greater changes were observed in men who lost 5 pounds or more and those with higher serum cholesterol at baseline. There was no significant reduction in CAD mortality or incidence in the group of men who were counseled.

A series of short-term metabolic studies where selected patients with CAD reduced their dietary saturated fat and/or increased polyunsaturated fat intake demonstrated a reduction elevated total Cholesterol and LDL-C by as much as 10-20%. However, because of variable compliance, trials of diet and counseling in the primary care setting usually achieve much smaller average reductions in serum cholesterol in asymptomatic persons (0-4%). The results in the primary care setting also tend to be inconsistent when compared to individual who are seen out of the office setting by a nutritionist or specially trained dietitian.

Ongoing studies are presently examining the efficacy of cholesterol screening and intervention in primary care settings in the U.S. More stringent diets can produce larger reductions in cholesterol but long-term data in asymptomatic persons are limited. Two trials involving women at risk for breast cancer where fat intake was lowered to 20% of calories demonstrated a reduction of total cholesterol in the range of 6-7% over a 1-2 year period of time.


While we have sufficient evidence to demonstrate that diet, lowering saturated fat intake and cholesterol intake, does reduce the risk of CAD, it is recognized that results are lower when the counseling and treatment program is administered in the primary care setting. The reason for this is based on several problems.

  • Most physicians do not have the education, skill or experience to support their patients.
  • The primary care setting is not the best place to get results as the physician has too little time to spend with his patient. Simply giving the patient a diet sheet does not work. Time must be spent with the patient:

  1. To instruct them in the most appropriate diet.
  2. To present them with a very specific diet and choices.
  3. To continually evaluate what the patient is doing to look at what they are eating and where they may be failing.
  4. To encourage them to make progressive, steady positive changes.
  5. To match results of blood testing with what they are doing with their diet.
  6. To continually work to keep them on target.
  7. To support and help them in every way possible.


When the physician works directly with the patient the cost of care goes up. Making dietary counseling prohibitive to all but a few people.

Insurance companies often do not pay for nutritional or preventive health services this means that only the sickest and most needy can get help. It effectively eliminates prevention of problems and leaves the physician to work with the sickest patients who need the most time and effort and will likely get the least results.