High cholesterol is a major contributing factor for heart attacks and stroke, the first and fifth leading causes of death in our country. While the traditionally recommended goal for total cholesterol is to achieve a level of less than 200mg/dL, we know from observational studies such as the Framingham Heart Study and the China Study that achieving a level of less than 150mg/dL is associated with a near absence of cardiovascular events. According to the CDC, more than 95 million adults have total cholesterol levels greater than 200mg/dL, and nearly 30 million have levels over 240mg/dL.(1)
Current guidelines recommend treating high cholesterol based on a patient’s level of risk. Those who have defined cardiovascular disease (prior stroke, heart attack, coronary stent, coronary artery bypass surgery, peripheral vascular disease, aortic aneurysm, etc.), diabetes, or inherited forms of high cholesterol where the LDL (bad cholesterol) level is greater than 190mg/dL automatically qualify for statin medications, as these have been shown to reduce future adverse events regardless of baseline cholesterol numbers. A fourth category of patients eligible for treatment are those who do not meet any of the aforementioned criteria, but have an estimated risk of having a heart attack or stroke over the next 10 years of more than 7.5%, as calculated by something called the pooled cohort equation. You can find the calculator here if you want to assess your own risk and you have a recent cholesterol profile available.
Can changes in diet have a significant influence on cholesterol levels? If so, what’s the best diet to follow? As physicians, we all too often tend to give generic advise such as “watch what you eat”, or “try to cut back on fatty foods”.
We know from the large 1980s observational China Study (2), which followed 6,500 adults in various parts of China, that the average cholesterol among the more plant-based Chinese was 127mg/dL compared with an average level of 215mg/dL in the United States. This was associated with a mortality rate from coronary artery disease that was more than fifteen times lower. In Dr. Dean Ornish’s Lifestyle Heart Trial (3), which followed 48 patients with coronary disease from 1986 to 1992, those that consumed a plant-based diet along with other lifestyle changes achieved a 30% greater drop in their LDL cholesterol after 1 year compared to a group following “standard dietary advice”. At 5 years, they maintained a 20% reduction in cholesterol compared with baseline, while completely avoiding cholesterol lowering medication. In 1985, Dr. Caldwell Esselstyn demonstrated an average drop in total cholesterol from 266mg/dL to 132mg/dL in 23 patients with severe vascular disease who began a plant-based diet which excluded all fats.(4)
More recently, a 2003 study by David Jenkins including 46 patients evaluated whether inclusion of certain “portfolio foods” as part of a low saturated fat diet would reduce cholesterol more than a low saturated fat diet alone or a low saturated fat diet combined with a low dose statin medication (20mg Lovastatin).(5) The “portfolio foods” included plant sterols, soy proteins, nuts, and viscous fiber from foods like oats, barley, psyllium, okra, and eggplant. After one month, there was a roughly 30% greater drop in LDL levels in the diet which included portfolio foods compared with the low saturated fat diet alone (see graph below). This was similar to what was achieved in the group taking the Lovastatin. Additionally, the ratio of bad cholesterol to good cholesterol dropped substantially (meaning the good cholesterol levels did not drop along with the bad cholesterol) in the dietary portfolio group, but actually increased (the good cholesterol levels dropped by a greater percentage than the bad cholesterol) in the group eating a low saturated fat alone diet. Finally, C-reactive protein, a marker for inflammation that has been associated with cardiovascular disease, also dropped about 30% in the group consuming portfolio foods, similar to what was seen in the group taking Lovastatin.
David Jenkins completed a larger study in 2011 involving 351 participants, which again confirmed the superiority of including portfolio components in addition to a low saturated fat, therapeutic diet, in lowering cholesterol.(6)
An American Heart Association Presidential Advisory released in June 2017 reinforced the benefit of lowering the intake of dietary saturated fat and replacing it with polyunsaturated and monounsaturated fats, which not only lower the LDL cholesterol level and maintain a healthier LDL to HDL cholesterol ratio, but are also associated with a roughly 30% reduction in cardiovascular disease.(7) Plant-based foods that are high in polyunsaturated fats include walnuts, flaxseeds, chia seeds, and soy beans, all of which contain the the omega-3 fatty acid ALA. Monounsaturated fats can be found in olives and olive oil, avocados, and many nuts.
In conclusion, dietary modification can have a significant impact on lowering LDL cholesterol levels, and in turn lessening the risk of cardiovascular disease. Patients should focus on replacing saturated fats which polyunsaturated and monounsaturated fats in their whole foods forms (rather than oils), as this has also been shown to reduce the risk of cardiovascular disease. Finally, patients should try to include “portfolio foods” such as soy, nuts, plant sterols, and viscous fibers in their diet.
1. Centers for Disease Control and Prevention. “High Cholesterol Facts”. https://www.cdc.gov/cholesterol/facts.htm.
2. Campbell, T.C. The China Study. 2005.
3. Ornish, Dean, et. al. “Intensive Lifestyle Changes for Reversal of Coronary Heart Disease”. JAMA. 1998 Dec 16;280(23):2001-7.
4. Esselstyn, Caldwell. Prevent and Reverse Heart Disease. 2008.
5. Jenkins, et al. “Effects of a Dietary Portfolio of Cholesterol-Lowering Foods vs Lovastatin on Serum Lipids and C-Reactive Protein”. JAMA. 2003;290(4):502-510.
6. Jenkins, et al. “Effect of Dietary Portfolio of Cholesterol-Lowering Foods Given at 2 Levels of Intensity of Dietary Advice on Serum Lipids in Hyperlipidemia: A Randomized Controlled Trial. JAMA. 2011;306:831-9.
7. Sacks, Frank, M. et. al. “Dietary Fats and Cardiovascular Disease: A Presidential Advisory From the American Heart Association”. Circulation. 2017;135:00-00.