The U.S. Dietary Guidelines Advisory Committeeís (DGAC) recommendations for new nutritional guidelines were released in mid-June and included saturated fat guidelines to...limit saturated fatty acid intake to less than 7% of total calories and substitute instead food sources of mono- or polyunsaturated fatty acids...and limit cholesterol-raising fats (saturated fats exclusive of stearic acid and trans fatty acids) to less than 5-7% of energy.

In a presentation at this years IFT, Gerald McNeill, Ph.D., vice president of R&D at Loders Croklaan, indicated science does not support recommendations to lower saturated fat intake or reclassify stearic acid as a non-cholesterol-raising fat.

ìThe Framingham Heart Study commenced in 1948 and included 15,000 participants over three generations.2 Correlations between dietary constituents and coronary artery disease (CAD) risk factors were performed every two years and showed that ...low levels of high-density lipoprotein (HDL) cholesterol are as much a risk factor for CAD as high [levels of] low-density lipoprotein (LDL) cholesterol...The best simple test for predicting CVD is the ratio of total:HDL cholesterol.

Total:HDL ratio correlates very well with risk of heart disease (see chart Predictors for Heart Disease Risk). At high HDL levels (>65mg), the risk of heart disease is low, even with a high LDL. Conversely, at low HDL levels (<45mg), the risk of heart disease is high--even with a low LDL.

A meta-analysis assessed data from 60 controlled studies that included trans fat and different kinds of saturated fat and found both were shown to increase LDL cholesterol3. McNeill noted a reduction in dietary saturated fat of 5% of diet would yield a maximum reduction of 5 units for LDL. A person with an LDL level of 220 is considered to be at high risk of heart disease. After reduction of 5% saturates in the diet, the new LDL level will be 215. This person is clearly still at high risk,4 he said.

However, changes in HDL paint a different picture. Saturated fats increase HDL more than any other kind of fat. If only HDL were considered, saturated fat would be the healthiest fat. When assessing total:HDL ratios, saturates neither increase nor decrease it.

A more recent paper assessed 11 observational studies, including 344,696 participants which spanned 4-10 years5, and found saturates were no different in their CVD risk effects than monounsaturates; they were, in fact, more favorable than carbohydrates. And, the most recent meta-analysis also concluded saturated fat does not increase CVD risk.6

According to McNeill, Is a reduction of 3-5% saturated fat a reasonable target? Absolutely not.  Most dietary saturated fat comes from meat and dairy. To achieve a saturated fat reduction of 5% of the diet, the total U.S. population would have to reduce meat and dairy intake by 60%. Even 5% reduction of saturates has a very small effect on LDL. The government should focus its resources on issues that have a bigger impact.  NS

For more information:

Loders Croklaan * Channahon, Ill.
Gerald McNeill *

2  Castelli WP. 1998. Can J Cardiol. 4(supplA):5A10A.
3  Mensink RP, et al. 2003. Am J Clin Nutr 2003;77:114655.
4 Calculated from Mensink's data, who presented the results for a change of 1% of diet, which was then multiplied by five and converted from mmoles/L (EU) to mg/dL (U.S.).
5  Jakobsen MJ, et al. 2009. Am J Clin Nutr. 89:1425-1432.
6 Siri-Tarino PW, et al. 2010. Am J Clin Nutr. 91(3):497-9.