If You’re Over 65, You’re Almost Definitely Low in 2 Key Vitamins

If you’re 65 or older and feeling a bit off, it could be because you’re running low on key vitamins for seniors—specifically, vitamins D and B12. In a study published in Nutrients, researchers explored how genetics, lifestyle, and environmental factors affect healthy aging. When they reviewed 1,000 blood samples taken from participants ages 65 to 93, they found that more than half were not getting enough vitamin D, and one in four had a vitamin B12 deficiency.

Further research reinforces just how common these nutrient shortfalls are as we age—and the health risks they pose. A 2023 study published in Frontiers in Nutrition reported that more than half of U.S. adults over age 50 are vitamin D deficient or insufficient, noting that low levels are linked with increased risk of chronic diseases such as heart disease, diabetes, cancer, and brain disorders.

In addition, 2025 research published in Brain Disorders highlights that vitamin B12 deficiency remains widespread among older adults, warning that low levels are associated with cognitive issues and nerve-related problems.  

Yet across these studies, researchers weren’t entirely surprised. They explain that aging brings natural changes that can make it harder for the body to absorb, convert, and store certain nutrients. As a result, older adults are more likely to develop certain micronutrient deficiencies without making key dietary tweaks. 

How to get more vitamin D and B12

The body makes vitamin D when sunlight hits your skin. According to 2023 research published in Photochemistry and Photobiology, most people need about five to 10 minutes of sun exposure for adequate vitamin D production—though if you live somewhere wintery, that can increase to up to 45 minutes of midday sunlight. 

However, “Older adults are prone to a vitamin D deficiency due to changes in their skin’s ability to convert this vitamin into the active form used by the body,” says Steven Starks, MD, MBA, DFAPA, a board-certified geriatric psychiatrist and medical educator. To shore up any gaps, fatty fish, eggs, and fortified cereals and juices are good dietary sources of vitamin D. 

Vitamin B12 absorption also declines with age. “Seniors are more likely to develop a vitamin B12 deficiency because their stomachs produce less acid,” Dr. Starks explains. “It’s the acidity that helps our bodies absorb this vitamin.” Among the foods naturally high in vitamin B12: salmon, liver, clams, and dairy products.

When to see a doctor

Vitamin D and B12 are crucial vitamins for healthy aging. Low levels of vitamin D can lead to health problems, including bone and muscle pain, high blood pressure, and depression. A B12 deficiency can cause tiredness, weakness, constipation, loss of appetite, weight loss, and anemia.

“Doctors will typically check your levels if there’s an identifiable change in your health,” says Dr. Starks.

He says to ask your doctor about checking your vitamin D levels if you’re experiencing:

• A change in your memory or thinking.
• Differences in your mood, like depressed, low, or sad moods.

And ask about your vitamin B12 levels if you have:

• Unusual sensations, such as numbness or tingling.
• A difference in your gait (walking pattern).
• Fatigue.
• Memory problems.

If you’re deficient, your doctor may recommend you take these vitamins as a dietary supplement to get your levels back in check.

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