A new study has found that drinking one to three cups of black caffeinated coffee per day is linked to a lower risk of death from all causes and death from cardiovascular disease, but adding sugar and saturated fat in large amounts may eliminate these benefits.
What the Research Says
The study, published in The Journal of Nutrition, examined the relationship between coffee intake, including the amount of added sugar and saturated fat, and mortality among United States adults.1
They found that consuming at least one cup of caffeinated coffee daily was associated with a 16% lower risk of all-cause mortality and mortality from cardiovascular disease.
Two to three cups reduced the risk by 17%. Beyond three cups, however, no additional reductions were observed, and the benefits for cardiovascular disease mortality weakened when more than three cups were consumed.
Researchers also found that consuming black coffee and coffee with low levels of added sugar and saturated fat was associated with a 14% lower risk of all-cause mortality compared with no coffee consumption. However, the reduced risk was not observed when high amounts of saturated fat and sugar were added.
“The reality is, most of us don’t just drink coffee alone,” Fang Fang Zhang, Ph.D, senior author of the study and the Neely Family Professor at the Friedman School.
“Although we might think, anecdotally, that yes, sugar and fat maybe weaken the benefits of coffee consumption, we wanted to really generate some evidence,” Zhang added.
How the Study Was Conducted
Zhang and her team used data from the National Health and Nutrition Examination Survey from 1999 to 2018, linked to National Death Index Mortality Data, which included a nationally representative sample of 46,222 adults aged 20 years and older.
Researchers defined “low added sugar” as granulated sugar, honey, or syrup under 5% of the FDA’s Daily Value, 2.5 grams per 8-ounce cup, or approximately half a teaspoon of sugar.
Meanwhile, “low saturated fat” was defined as 5% of the FDA Daily Value from milk, cream, and half-and-half.
That’s equivalent to 1 gram per 8-ounce cup, or:
- 5 tablespoons of 2% milk
- 1 tablespoon of light cream
- tablespoon of half-and-half
The Significance of the Results
This study is one of the first to examine how what we put in our coffee may be as important as drinking it, said Liz Weinandy, MPH, RD, a registered dietitian nutritionist and instructor of practice in medical dietetics at The Ohio State University Wexner Medical Center.
While the researchers did not examine how or why coffee on its own may have protective effects, other studies suggest that caffeine may help speed up your metabolism and improve insulin sensitivity.2
Coffee beans also have flavonoids, which have been linked to many health benefits, including reducing the risk of chronic diseases.3
On the other hand, research has shown that high amounts of sugar and saturated fats can harm glucose metabolism and insulin sensitivity, leading to obesity.4
“This is just one study, but it certainly supports what we already know—sugar and saturated fat are not good for human health, and we should limit both in our diets,” Weinandy said.
Should You Alter Your Coffee Order?
While many nutrition-based studies offer a cautionary message about what to stay away from, Zhang said she feels the overall message from this study is positive:
“Enjoy your coffee if you’re a coffee drinker,” she said. “It’s a good thing that we saw the benefits of drinking coffee. Just watch what you add to it. If you enjoy some milk, you can add it, if you enjoy some sugar, you can do that—try not to go beyond the threshold.”
How Does This Apply to Real Life?
Based on this study, if you are a coffee lover, considering how you take it might make a difference. Love a good caramel latte or extra-sweet frappuccino? Well, here’s some food (or should we say, drink) for thought. Opting for black coffee or dialing back on the sugar and cream might not just save you a few calories; it could actually help regulate your blood sugar levels, particularly for women and older adults.
Additionally, these findings remind us of the importance of personalized health choices. Coffee consumption isn’t a one-size-fits-all matter—it may have varying effects based on factors like age, gender and individual health profiles. Reflecting on how these variables apply to your own habits could help you make informed decisions about your daily coffee intake.
By staying mindful of preparation methods and moderating consumption where necessary, coffee can remain an enjoyable part of your routine while potentially contributing to improved metabolic wellness. Unfortunately, this study did not address whether using sugar substitutes impacts the evaluated outcomes.
What Did The Study Find?
After conducting analyses, the researchers found that drinking 2 cups of coffee each day appeared to be linked to slightly better glucose metabolism compared to no coffee at all. Specifically, this was seen in lower levels of markers like HOMA-IR and fasting insulin, which are related to insulin resistance.
When breaking it down by coffee type (black vs. with sugar or cream), drinking up to 1 cup of black coffee daily was significantly associated with better glucose metabolism. However, coffee with sugar or cream didn’t show any clear benefits for these markers. This suggests that plain black coffee might have some positive effects on how the body processes sugar.
The analysis showed differences between men and women. For women, drinking two or more cups of coffee daily, especially black coffee, was associated with better levels of health markers related to blood sugar regulation (meaning their blood sugar and insulin levels seemed better controlled).
For instance, women who drank two or more cups of coffee had lower odds of issues with insulin resistance and elevated fasting insulin compared to those who didn’t drink coffee at all. The associations were stronger with black coffee, suggesting it might have unique health benefits. However, these benefits were not observed in men or in individuals who added sugar or cream to their coffee. This indicates that the way coffee is consumed and individual differences, like sex, may play important roles in its potential effects on health.
The study also observed a pattern of higher coffee intake being linked to better glucose metabolism in older adults. However, these results should be interpreted carefully, especially given the unique health factors that often apply to older populations.
This study comes with some limitations. Because it was cross-sectional, we cannot determine cause and effect. However, removing participants who had diseases or were on special diets for health conditions helps reduce the chance of reverse causation.
But it is important to note that there were trends when assessing the qualities of certain groups of participants. For example, heavy coffee drinkers tended to have a higher BMI and more education, eat more calories daily, exercise less and sleep fewer hours. Many of them were also current smokers. These factors may impact overall health, including blood glucose control.
The study also couldn’t account for different types of coffee (like decaf) or other caffeine sources (like tea or energy drinks), which may affect the results. Finally, coffee habits were measured only once, not allowing for changes in habits that may impact outcomes.