What Your Diet Has to Do with Your Hair Health | San Diego Scalp Specialist

What Your Diet Has to Do with Your Hair Health

By Kelly Moreno Vindel | The Scalp Report

Hair is one of the first places nutritional deficiencies show up — and one of the last places people think to look when their diet isn't supporting them. The connection between what you eat and the health of your hair and scalp is direct, significant, and largely underappreciated.

As a scalp wellness specialist in San Diego, I always ask new clients about their diet and nutrition. Here's why it matters — and what to focus on.

Hair Is Made of Protein — So Protein Comes First

Hair is composed almost entirely of a protein called keratin. Without adequate dietary protein, your body simply doesn't have the building blocks it needs to produce strong, healthy hair.

Signs you may not be getting enough protein:

• Increased shedding

• Hair that feels weak or breaks easily

• Slow growth

• Dull, lifeless texture

How much is enough? Most adults need roughly 0.7–1 gram of protein per pound of body weight daily. Good sources include eggs, chicken, fish, legumes, Greek yogurt, and tofu.

Iron and Ferritin: The Most Overlooked Hair Nutrient

Iron deficiency is one of the most common — and most underdiagnosed — causes of hair loss, particularly in women. What makes this especially tricky is that you can have low ferritin (stored iron) without being clinically anemic, and standard bloodwork doesn't always check ferritin unless you specifically ask for it.

Low ferritin essentially starves the hair follicle, pushing hairs into the resting and shedding phase prematurely.

If you're experiencing diffuse shedding (loss all over the scalp, rather than in patches), ask your doctor to check your ferritin level specifically — not just hemoglobin.

Iron-rich foods: red meat, spinach, lentils, chickpeas, pumpkin seeds, dark chocolate.

Note: vitamin C significantly improves iron absorption. Pair iron-rich foods with a source of vitamin C for best results.

Vitamin D

Vitamin D receptors are found in hair follicles, and research consistently links low vitamin D levels to various types of hair loss. Many people — even in sunny San Diego — are deficient, particularly in fall and winter when sun exposure decreases.

Getting your vitamin D level checked with routine bloodwork is easy and worth doing if you're experiencing hair changes.

Biotin: More Nuance Than the Marketing Suggests

Biotin (vitamin B7) is heavily marketed for hair growth — and it does play a role in keratin production. However, true biotin deficiency is actually rare, and taking biotin supplements when you're not deficient may not do much.

The exception: if you're deficient (which can be tested), supplementing genuinely helps. If you're not, the evidence for extra biotin improving healthy hair is limited.

Zinc

Zinc supports hair tissue growth and repair, and helps keep the oil glands around follicles working properly. Zinc deficiency has been linked to hair loss and scalp conditions including dandruff.

Zinc-rich foods: oysters, beef, pumpkin seeds, hemp seeds, chickpeas, cashews.

Omega-3 Fatty Acids

Omega-3s support scalp health by reducing inflammation and helping maintain the scalp's natural moisture barrier. A diet low in healthy fats can contribute to a dry, inflamed scalp.

Good sources: fatty fish (salmon, sardines, mackerel), flaxseeds, chia seeds, walnuts.

What to Limit

Just as important as what you add is what you reduce. A diet high in the following can contribute to scalp inflammation and hair issues:

• Refined sugar and processed carbohydrates — spike insulin and can increase androgen levels, which affects hair follicle sensitivity

• Alcohol — depletes zinc, B vitamins, and iron; dehydrates the scalp

• Crash dieting or very low calorie intake — rapid caloric restriction is one of the most reliable triggers of telogen effluvium (stress-related hair loss)

The Bottom Line

No shampoo, scalp treatment, or supplement can fully compensate for a diet that isn't supporting your hair from the inside. The best hair care routine combines what you put on your scalp with what you put in your body.

If you're experiencing hair changes and want a professional scalp assessment alongside lifestyle guidance, I'm here.

👉 Book a scalp consultation in San Diego

Kelly Moreno Vindel is an independent hairstylist in San Diego specializing in scalp wellness, lived-in color, and precision cutting. Located at 435 Tenth Ave, San Diego, CA 92101