When the Body Speaks Up: 4 Signs You May Need to Pay Closer Attention to Vitamins and Minerals

You eat reasonably well, you buy fruit every week, and still you feel drained, catch every cold going around the office, and wake up tired. Before you blame the weather or your age, ask yourself four simple questions: Are you taking medication? Are you under constant pressure? Do you smoke? Have you cut animal products from your plate? Nutrition experts point out that each of these everyday situations can quietly shift the balance of key vitamins and minerals in the body, often long before you notice anything is off.

A Hollywood Star Who Learned This the Hard Way

Oscar-winning actress Gwyneth Paltrow, known for her carefully planned diet and rigorous fitness routine, wrote in her GOOP newsletter that blood tests showed her vitamin D levels were the lowest her doctors had ever seen, and that she had the early stages of osteopenia, a thinning of bone density. Her doctors prescribed a high-strength vitamin D supplement and advised her to spend a bit more time in the sun. Her story, covered at the time by NPR, is a good reminder that even a "clean" diet does not automatically cover every nutrient, and that lifestyle habits, like avoiding the sun, can matter just as much as what's on your plate.

A reader shared a similar experience with us: after months of fatigue she put down to a busy job, a routine blood test showed her iron was low. "I thought I was just tired from work," she wrote. "A few changes to my meals and a supplement my doctor recommended, and within a couple of months I felt like myself again."

Vitamin C: The Familiar First Line

Vitamin C plays an important role in the normal function of the immune system. As soon as you feel something coming on, many of us instinctively reach for foods rich in vitamin C, such as citrus fruits, kiwi, bell peppers and leafy greens. Onions and garlic are also popular kitchen helpers during cold season, valued more for their flavor and plant compounds than for their vitamin C content.

It's worth keeping expectations realistic: a large Cochrane review of vitamin C and the common cold found that regular vitamin C intake did not prevent colds in the general population, though it may slightly shorten how long they last. Vitamin C also helps the body absorb iron from plant foods, a combination we explore in Foods That Improve Nutrient Absorption. For a warming winter habit, you might also enjoy Warm Water with Turmeric Against Winter Troubles.

But what should you do when things are more complicated than a seasonal sniffle?

1. Are You Taking Medication?

Many doctors will recommend a dietary supplement alongside certain medications. Medicines often have side effects, and some can affect how the body absorbs or excretes vitamins and minerals, so it makes sense to keep an eye on your nutrient intake while you are taking them.

According to the NIH Office of Dietary Supplements magnesium fact sheet, long-term use of proton pump inhibitors (common heartburn medications) and some diuretics can lower magnesium levels. The NIH vitamin B12 fact sheet notes that metformin, often used for type 2 diabetes, and acid-reducing medicines may reduce B12 absorption. Other medicines, including some oral contraceptives, have been linked to lower vitamin B6 status.

The good news is that many of these nutrients are easy to find on your plate:

• Vitamin C: oranges, mandarins, kiwi, bell peppers, broccoli, kale and spinach.


• Magnesium: spinach, pumpkin seeds, almonds, beans, whole grains and dark chocolate.


• Vitamin B6: chickpeas, potatoes, bananas, poultry and fish.


• Vitamin B12: found naturally only in animal foods, such as fish, meat, eggs and dairy, or in fortified foods.

Important: never start a supplement without talking to your doctor or pharmacist first, as some supplements can interact with medications.

2. Do You Feel You Are Under Stress?

Daily pressure, stress at work and at school all take their toll. When we are stressed, we often eat more hurriedly and less carefully, and the body's demand for certain nutrients may change. B vitamins, which support the normal function of the nervous system and energy metabolism, are frequently mentioned in this context.

A 2019 meta-analysis published in the journal Nutrients found that B-vitamin supplementation was associated with modest improvements in self-reported stress in healthy and at-risk adults. Researchers have also described a possible two-way link between stress and magnesium in a 2020 review in Nutrients, suggesting that stress may increase magnesium loss, while low magnesium may in turn affect how we handle stress. The evidence is still developing, so a varied diet with whole grains, legumes, leafy greens, nuts and eggs remains the best foundation.

What you avoid matters too: read 7 Everyday Foods That Quietly Feed Your Stress (Number 5 Might Surprise You) to see which ordinary foods may add extra strain.

3. Are You a Smoker?

Smoking affects how the body absorbs and uses several vital vitamins and minerals. The best-documented example is vitamin C: the NIH Office of Dietary Supplements states that people who smoke need 35 mg more vitamin C per day than nonsmokers, because smoking increases oxidative stress and uses up the vitamin faster.

Vitamin D also deserves attention. Some studies have associated smoking with lower vitamin D levels, and smokers who spend little time outdoors may be at greater risk. Vitamin D is produced in the skin when it is exposed to the sun's ultraviolet rays, which is why it is often called the "sunshine vitamin." A brisk walk outdoors at least three times a week for 15 minutes or more, ideally in a forest or park, is a pleasant way to support your vitamin D levels, while also giving your lungs fresh air. Keep in mind that, according to the NHS, between October and March the sun in northern latitudes is often too weak for the skin to make enough vitamin D, which is why many people consider a supplement in the colder months.

Of course, the most effective step for your health is to quit smoking altogether. A diet rich in colorful fruits and vegetables can support your body along the way.

4. Are You Vegan or Vegetarian?

A well-planned plant-based diet can be healthy and nutritious, as the Academy of Nutrition and Dietetics notes in its position paper on vegetarian diets. Still, two nutrients deserve special attention: iron and vitamin B12.

Vitamin B12 is found almost exclusively in animal foods, and plant foods do not provide reliable amounts. The Vegan Society itself advises vegans to eat B12-fortified foods or take a B12 supplement. For people on a fully vegan diet, fortified foods and supplements are the only reliable route.

Iron from plants (non-heme iron) is absorbed less efficiently than iron from meat. Harvard Health Publishing recommends beans and lentils, dark leafy greens, tofu and iron-fortified cereals. Research from Sweden, described by the authors in The Conversation, found that teenage girls who avoided meat had a notably higher risk of low iron. At the same time, a 2025 review in Current Nutrition Reports notes that results differ between studies, and that well-planned vegan diets can provide plenty of iron.

A simple trick helps: pair iron-rich plant foods with a source of vitamin C, such as lentils with peppers or oatmeal with orange slices. You'll find more clever combinations in The Kitchen Trick Your Body Is Begging You to Learn.

Listen to Your Body, but Check with a Professional

Fatigue, frequent colds or low mood can have many causes, and a vitamin shortfall is only one of them. If any of the four situations above sounds familiar, the smartest first step is a conversation with your doctor and, if needed, a simple blood test. That way, you can choose the right foods and, if necessary, the right supplement, instead of guessing.