Gastroenterologist Warns: These Symptoms May Reveal Hidden Nutrient Deficiencies

In our fast-paced modern lives, it's easy to grab convenient foods, skip meals, or follow fad diets without paying close attention to what our bodies truly need. But behind that daily fatigue, brittle nails, or frequent bloating may lie a deeper problem—nutrient deficiency. A leading gastroenterologist has highlighted several subtle yet crucial signs that your body may be lacking essential vitamins and minerals, with one particularly common symptom showing up in more people than you might expect.

Understanding these signs isn’t just about optimizing your health—it’s about avoiding long-term complications that can develop quietly over time.

1. Chronic Fatigue That Won’t Budge

Everyone feels tired occasionally, especially after a poor night’s sleep or a hectic day. But if you’re constantly running on empty—even after eight hours of rest—it could point to deficiencies in iron, vitamin B12, or folate.

Iron deficiency, for instance, reduces the blood's capacity to carry oxygen, leading to persistent exhaustion. Vitamin B12, crucial for nerve function and red blood cell production, can also cause weakness, brain fog, and low energy when deficient.

If you find yourself depending heavily on caffeine just to function, it might be time to check your micronutrient intake.

2. Cracks at the Corners of Your Mouth

This uncomfortable, often overlooked symptom—known as angular cheilitis—is a telltale sign of deficiencies in iron, B vitamins (especially riboflavin and B2), or even zinc. It often starts with dryness at the corners of the lips and can progress to painful splits that make smiling or eating uncomfortable.

The gut specialist notes that this is often seen in patients with digestive issues that affect nutrient absorption, such as IBS or celiac disease. If lip balms and hydration aren’t solving the problem, an internal issue could be the cause.

3. Brittle Nails and Thinning Hair

Your hair and nails are often the first to show signs of poor nutrition. Biotin (vitamin B7), iron, protein, and zinc are key for healthy hair and nail growth. Deficiency in any of these can cause your nails to become brittle, ridged, or split easily, while your hair may shed excessively, become dull, or thin at the roots.

One common mistake, says the gastroenterologist, is assuming these changes are purely cosmetic or age-related, when they could actually be internal warning signs.

4. Frequent Digestive Disturbances

Gas, bloating, and constipation might not just be caused by something you ate—they could signal poor gut health due to nutritional imbalances. For example, a lack of magnesium can slow down bowel movements, while insufficient fiber and hydration further contribute to irregularity.

Additionally, those who avoid dairy, gluten, or other major food groups without proper substitution may miss out on calcium, B vitamins, or other nutrients essential for digestive function.

The gut is often called the “second brain,” and when your digestion is out of balance, it often reflects a wider systemic problem.

5. Tingling, Numbness, or Pins and Needles Sensations

Here it is—the symptom the gastroenterologist says is “super common” and frequently misdiagnosed: tingling or numbness in the hands, feet, or extremities. Often dismissed as bad circulation or posture-related, these sensations can actually indicate a deficiency in B vitamins, particularly B12.

B12 plays a vital role in maintaining nerve health. Without it, nerves can misfire, leading to a "pins and needles" feeling that may come and go or persist. In more advanced cases, this can progress to coordination issues, muscle weakness, or even cognitive difficulties.

The specialist warns that vegans, vegetarians, older adults, and those with digestive disorders are especially at risk of B12 deficiency, and this symptom should never be ignored.

6. Mood Swings and Brain Fog

Nutrient imbalances don’t just affect the body—they hit the mind too. Low levels of omega-3 fatty acids, vitamin D, magnesium, and iron have all been linked to depression, anxiety, and difficulty concentrating.

If you’re experiencing unexplained mood changes, irritability, or foggy thinking, your diet may be falling short. A blood test can often confirm whether low nutrient levels are contributing to your mental and emotional symptoms.

The doctor emphasizes that these deficiencies don’t always show up on standard check-ups unless specifically tested for—so if your symptoms are persistent, it’s worth digging deeper.

7. Pale Skin or Dark Under-Eye Circles

That “washed out” look could be more than tiredness—it might be anemia. Iron and B12 deficiencies can result in paleness, particularly in the inner eyelids, lips, and fingernails. In some cases, people also develop dark circles under their eyes as the skin becomes more translucent due to reduced blood flow.

While cosmetics can cover these signs, they shouldn’t hide the fact that something may be missing inside. A comprehensive nutritional panel could be revealing.

8. Restless Leg Syndrome

A strange urge to move your legs—especially at night—may be more than a sleep issue. Restless leg syndrome (RLS) has been strongly linked with iron deficiency, even in people who don’t have full-blown anemia.

The gastroenterologist says that many patients with RLS report improved symptoms after correcting iron levels through diet or supplements, reinforcing how even neurological issues can stem from nutritional roots.

9. Slow Healing Wounds or Frequent Bruising

If you find that cuts, scrapes, or bruises take longer to heal—or appear without any trauma—it could be a sign that your body is missing vitamin C, vitamin K, or zinc. These nutrients help with tissue repair, collagen production, and blood clotting.

This symptom may be especially relevant to older adults, people with high stress levels, or smokers, who all tend to have higher nutrient requirements.

10. Persistent Mouth Ulcers or Tongue Sensitivity

A sore or swollen tongue, or frequent canker sores, can indicate deficiencies in B vitamins (especially B12, folate, and B6), as well as iron and zinc. These nutrients support tissue regeneration, immune function, and inflammation control.

If ulcers or tongue sensitivity become recurrent, it’s worth exploring if poor nutrient intake or absorption is the underlying cause.

What Can You Do?

Recognizing these signs is only the first step. The next is taking proactive measures:

• Get Tested: Routine blood work often includes basic vitamin and mineral markers. Ask your doctor about testing for B12, iron, folate, vitamin D, magnesium, and zinc if you suspect a deficiency.

• Eat a Balanced Diet: Focus on whole foods—vegetables, fruits, legumes, whole grains, nuts, seeds, lean proteins, and healthy fats. Limit ultra-processed foods.

• Consider Supplements (If Needed): Some people may need supplements due to medical conditions, dietary restrictions, or lifestyle factors. Always consult a healthcare provider before starting them.

• Support Gut Health: Your digestive system plays a crucial role in absorbing nutrients. Treating gut issues can help improve nutrient uptake.

Your body often whispers before it screams. The cracks, tingles, fatigue, and fog—these are messages. As the gastroenterologist puts it, “You don’t need to be malnourished to be deficient.” In fact, nutrient deficiencies can occur even in those with normal weight and calorie intake.

So listen carefully. That super common symptom might just be your body’s way of asking for help.