How much coffee is too much? The FDA notes that you can get away with drinking about four or five cups, or 400 milligrams of caffeine, each day without suffering negative effects. (This is true as long as you don’t have a sensitivity to it and you aren’t pregnant or breastfeeding.) However, new research suggests that the more caffeine you consume, the more likely you are to suffer from a vitamin D deficiency.
A recent study published online in the International Journal for Vitamin and Nutrition Research tested the link between vitamin D and caffeine by analyzing information from the 2005 National Health and Nutrition Examination Survey. Medical researchers from China and Brazil investigated data from over 13,000 participants between 30 and 47 years old. After adjusting for other variables, such as age, sex, race, physical activity, and diet, the research team confirmed that vitamin D levels decreased in participants as caffeine levels rose.
The researchers noted that the finding should be taken with a grain of salt. The effects of caffeine on vitamin D levels in adults older than 47 aren’t well known. Further research would also help prove that caffeine actually causes vitamin D levels to decrease.
Still, previous research suggests that this investigation has merit. American Bone Health states that drinking too much caffeine is bad for bone health because it can deplete calcium stores. Caffeine is a diuretic and could therefore cause the body to release more calcium through the urine. Overtime, reduced calcium levels can lead to bone loss. Since vitamin D is also linked to bone health, it isn’t a huge stretch to suggest that caffeine affects vitamin D levels, too.
Another study from the Journal of Steroid Biochemistry and Molecular Biology states that caffeine may interfere with the body’s ability to metabolize vitamin D. Researchers conducted the study because other investigators had not yet learned why caffeine depletes vitamin D levels in the body. After testing the effects of caffeine at a cellular level, the team determined that the drug alters the function of osteoblast cells, or cells that form new bone. The proteins inside the cells that use vitamin D also performed differently.
Vitamin D deficiency is not something that you should ignore. It can cause a wealth of symptoms, including a weak immune system (getting sick all the time), fatigue, bone and back pain, brittle bones, and depression. A long-term deficiency could even contribute to a serious health condition, such as heart disease, high blood pressure, and diabetes.
This doesn’t mean you have to give up coffee entirely. But, if you’re still banking on drinking multiple cups per day, it’s a good idea to monitor your calcium and vitamin D intake. Getting your daily allotment of both of these nutrients will prevent you from developing a deficiency. According to the National Institutes of Health, you should consume about 600 IU daily if you are between 50 and 70 years old, and 800 IU daily if you are older than 70. Reaching your goal is as easy as taking a daily supplement or eating four to five ounces of salmon.
If you’re willing to branch out, you can also try some coffee alternatives. Beverages like raspberry leaf tea and mushroom coffee are excellent substitutes that will reduce your caffeine intake but provide you with the same comfort of a hot mug in the morning.