Harvard Health Content API

In a 2025 randomized trial of about 1,000 people (ages 50 or older), followed for four years, those who took 2,000 international units of vitamin D₃ per day showed cellular signs that suggested they were aging more slowly compared with people who did not take the supplement. It’s unclear if this benefit would continue from taking daily pills longer than four years. Scientists do know that taking vitamin D₃ supplements is important for people with osteoporosis or with vitamin D deficiency (as determined by a blood test).

In May 2025, the FDA approved the first blood test to detect the early stages of Alzheimer’s disease. The test looks for several proteins associated with Alzheimer’s disease. About 80% of the time, the blood test is either highly positive or highly negative, a result that’s accurate more than 90% of the time. Doctors expect that the test will soon be covered by insurance. If that happens, the test will become the standard of care for people ages 55 and older with Alzheimer’s signs or symptoms.

A 2025 study of more than 11,000 people (average age 55), followed for about four years, those who walked more than 100 minutes a day had a 23% lower risk of chronic low back pain, compared with people who walked less than 78 minutes per day.

In a 2025 analysis involving about 200 million people, those who used cannabis had a 29% higher risk for sudden heart attacks or angina and twice the risk of premature death from cardiovascular disease, compared with people who didn’t use cannabis.

A 2025 study that involved 125,000 people (ages 40 to 69), who were followed for about a decade, found that both the quantity and variety of flavonoid intake were linked with significantly reduced risks of chronic disease and death from any cause.

Tennis leg refers to a strained calf muscle, usually the gastrocnemius. A person can injure the muscle during activity when planting the foot down hard or suddenly changing direction. This might happen during sports, such as tennis, or even while walking or jogging. Mature athletes, who are prone to injury, are vulnerable to the injury. Treatment can involve resting, elevating, and icing the calf muscle; wearing a compression sock; taking painkillers; getting physical therapy; and having surgery.

There are no medications to treat aortic stenosis (narrowing of the aortic valve), but several possibilities are currently being studied, including a class of drugs to treat diabetes and others that lower high lipoprotein(a) blood levels.

Few people get the recommended two fruits and three vegetables per day. Tips for helping people add more produce into their diets include starting small (making just one minor addition or substitution at a time and sticking with it for several weeks); choosing smarter snacks (like hummus and carrots or apples and peanut butter); sneaking pureed vegetables into pasta and other dishes; making smoothies and soups; and relying on frozen fruits and vegetables.