The research on caffeine's effect on cholesterol -- or other risk factors for heart disease -- is somewhat ambiguous. Caffeine is linked to modest elevations in cholesterol, but levels of harm depend on how much caffeine is consumed, whether it is consumed in coffee or tea and a person's genetic makeup.
Cholesterol Research
Drinking large amounts of unfiltered coffee can lead to small increases in cholesterol levels, according to MayoClinic.com. Coffee may also alter other known risk factors for coronary heart disease: blood pressure and homocysteine levels. However, there is no association with actual hypertension as opposed to transient increases in blood pressure. Additionally, coffee drinking seems to provide some protection against type 2 diabetes, which is also a risk factor for heart disease.
Genetic and Environmental Factors
Whether or not coffee is bad for you might depend on your genes, according MayoClinic.com. There is a fairly common genetic mutation that slows the rate at which some people metabolize caffeine. For these people, drinking as few as 2 cups of coffee per day can raise the risk of developing heart disease. Another relevant issue is lifestyle. For example, if some people who drink large amounts of coffee also smoke or have other unhealthy practices, it can make it difficult to separate the effects of caffeine from those of other substances.
Black Tea
Black tea, which contains fairly high levels of caffeine, can lower cholesterol levels, according to an October 2003 article in the "Journal of Nutrition." The authors reported that tea contains a substance that prevents cholesterol from being absorbed in the intestines. However, caution must be used when evaluating the results because the sample size was relatively small.
Caffeine May Protect Against Cholesterol
The blood-brain barrier protects the brain against harmful substances in the bloodstream that could damage the brain. According to a 2008 article in "BBC News," research published in the "Journal of Inflammation" indicates that coffee may protect the brain against leaks in this barrier that could increase the risk of developing Alzheimer's disease. According to earlier studies, high cholesterol levels can make this barrier "leaky." However, rabbits given a high-cholesterol diet for 12 weeks showed less damage if they were also given the equivalent of 1 cup of coffee per day.
References
- "Journal of Nutrition"; Black Tea Consumption Reduces Total and LDL Cholesterol in Mildly Hypercholesterolemic Adults; Michael J. Davies, et al.; October 2003
- Mayo Clinic; Nutrition and Healthy Eating: Coffee and Health: What Does the Research Say?; Donald Hensrud, M.D.
- "Pharmacology & Therapeutics"; Acute and Long-term Cardiovascular Effects of Coffee: Implications for Coronary Heart Disease; N.P. Riksen, et al.; February 2009
- BBC News: Daily Caffeine Protects Brain
