By Julianne Bierwirth, RD
Coffee has a chemical complexity that, through the roasting process, creates a broad range of vibrant flavor characteristics. This same molecular diversity is also responsible for a variety of health effects in humans. Caffeine is certainly the most well-studied, but it is far from the only pharmacologically active molecule extracted during a brew. Some of these chemicals are elusive, and their effects poorly understood. Others, after decades of research, have concrete benefits and detriments firmly borne out by data.
In this 8-part blog series, we delve into the myriad truths, half-truths, and indeed, fallacies, related to the impact that coffee has on your health. Is it good for you? Is it bad for you? Is it going to make your teeth brown? Does coffee make you smarter? Read on to find out.
PART 7: HEART HEALTH
For years coffee was considered to be bad for health in a variety of ways - heart health chief among them. The caffeine in coffee can raise your blood pressure as part of its work on the sympathetic nervous system. Your adrenaline pumps as part of your flight or flight response and you may even be able to feel your heart racing. If you have high blood pressure or conditions that predispose you to heart problems, drinking coffee may seem the last thing you want to do. Fortunately for enthusiasts coffee isn’t just okay for those with cardiovascular issues, it might soon be prescribed.
Caffeine does raise systolic (top number) blood pressure by up to 10 points, but only in non-habitual drinkers. As the body becomes accustomed to caffeine it adjusts cardiovascular responses to account for the additional boost. If your body didn’t respond this way we wouldn’t see caffeine dependence and withdrawal. By measures other than blood pressure including adrenal response and heart minute volumes (amount of blood pumped per minute by the heart) it seems that coffee has little effect in habitual drinkers.
Research has reliably found no long-term negative cardiovascular effect from drinking coffee, even in those who have cardiovascular disease. But obviously you cannot just drink to your heart's content, pun intended. There is something that stops you after maybe 3 or 6 or 10 cups. It might be the gastrointestinal effect, or an over-excitement that becomes unpleasant and distracting.
However, across years of research, scientists have not been able to define a safe upper limit because data on consumption levels greater than 600 mg caffeine are limited. That is not to say there isn’t a limit. Caffeine’s LD50, or the lethal dose at which 50% of people would die, is considered to be 80-100 cups of coffee as estimated from rat studies done in the course of drug trials. But there is a big gap between 6 cups a day and 80 for which we have basically no scientific understanding.
So if blood pressure and other health measures are not negatively affected in the long run, is coffee just a wash on the cardiovascular front? No. In fact, the research is leaning towards recommending several cups a day for the benefit of heart health and diabetes.
Some of the longest running observational health studies in existence see coffee intake inversely correlated to the risk of cardiovascular disease, heart failure, and stroke. For each additional cup of coffee, a 5-8% decrease in risk factor was seen up to six cups a day. This effect was so pronounced that the USDA, in their 2015 dietary guidelines, suggested that up to five cups of coffee a day can be included in a healthy diet. Additionally, the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recently lifted the recommendation to restrict coffee and caffeinated beverages.
The big caveat on all of this positive press is how you prepare your coffee. The healthiest for your heart is a black coffee without added milks or sweeteners. Added sugars and saturated fats can quickly negate the beneficial aspects of your morning joe, so go easy and instead find yourself a coffee that is delicious and unique served black. We at 1000 Faces would be glad to help you with that.
Sudano, I. et al. (2005) Cardiovascular effects of coffee: is it a risk factor? Progress in Cardiovascular Nursing, 20(2): 65-9.
Turnbull, D., Rodricks, J.V., Mariano, G.F., Chowdhury, F. (2017) Caffeine and cardiovascular health. Regulatory Toxicology and Pharmacology, 89: 165-85.
Gluckman, T. (2010) Ask an expert: how does caffeine affect the heart? Providence Health & Services. https://oregon.providence.org/forms-and-information/a/ask-an-expert-how. -does-caffeine-affect-the-heart/
Macmillan, A. (2017) Here’s another reason to feel good about drinking coffee. Time. http://time.com/5022060/coffee-health-benefits-heart/
Mattioni, A.V. (2014) Beverages of daily life: impact of caffeine on atrial fibrillation. Journal of Atrial Fibrillation, 7(2): 1133.
American College of Cardiology (2018) Is caffeine safe, protective for patients with Afib, arrhythmias? https://www.acc.org/latest-in-cardiology/articles/2018/04/16/16/27/is-caffeine-safe-protective-for-patients-with-afib-arrhythmias
USDA. (2016) 2015-2020 Dietary guidelines: answers to your questions. https://www.choosemyplate.gov/2015-2020-dietary-guidelines-answers-your-questions