14 Subtle Signs of Vitamin and Mineral Deficiencies You Need to Know

11. Sweaty Forehead for No Clear Reason

An oddly sweaty forehead—even in comfortable temperatures—can be a lesser-known sign of low vitamin D. Dr. Michael Holick notes that this is often one of the earliest clues, yet it’s easy to miss or blame on anxiety or mild exertion. With vitamin D deficiency impacting over a third of adults in the U.S., keeping an eye on unexplained forehead sweat may help you catch a deficiency early. Fortified foods, safe sun exposure, and supplements with your provider’s guidance can make a world of difference, especially if you’re feeling off in other subtle ways as well.

12. Regular Bloating, Gas, or Digestive Upset

While digestive complaints are easy to shrug off as diet or stress, persistent bloating, gas, or other “gut grumbles” can sometimes signal a lack of key nutrients including vitamin D, B12, zinc, and magnesium. Research increasingly supports the connection between digestive disorders—like IBS—and low vitamin D (BMJ Open Gastroenterology). Try incorporating more yogurt, beans, eggs, and dark chocolate for a balanced nutrient boost. If your digestive discomfort persists despite thoughtful changes, a conversation with a trusted provider will help you zero in on causes and next steps, all in the spirit of gentle, informed self-care.