While the effects of some nutrient deficiencies might sneak up on you — think: the fatigue you can't seem to shake or the muscle cramps that come up more regularly — some of them can make noticeable changes to your appearance.
A healthy diet not only supplies energy, but it also provides nutrients that are essential for healthy cell turnover, so it makes sense that nutrient deficiencies can wreak havoc on your skin, nails, hair and even gums.
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For instance, if you're not getting enough protein in your diet, it's possible you could experience hair loss and brittle nails, Amy Goodson, RD, CSSD, a registered dietitian in Dallas, tells LIVESTRONG.com. "For those who are vegan or vegetarian, it's very important to make sure they are consuming enough protein from plant-based foods like soy products, nuts, seeds, beans, lentils and possibly additional protein powders," Goodson says.
If you're struggling with one of these telltale signs of a nutrient deficiency, see your doctor right away. A medical exam can give you a clear diagnosis and help you get your diet back on track. And remember to always check with your doctor before taking any supplements.
1. Dry, Parched Skin
Sure, dry skin, especially in colder weather, may not be all that uncommon. But if your skin is feeling flakier than usual, a lack of healthy omega-3 fatty acids in your diet may be to blame.
Omega-3s help nourish your skin's lipid barrier, the layer of oils that keeps harmful germs and toxins out and essential moisture in, Kelly Franckowiak, RD, CDE, a registered dietitian with Kaiser Permanente in Atlanta, tells LIVESTRONG.com.
Without a sufficient amount of omega-3s, your skin loses moisture, which can lead to an unpleasantly scaly texture. You may even notice more wrinkles and visible aging due to skin dehydration. Avoid developing an omega-3 fatty acid deficiency by eating a diet rich in essential fatty acids. These foods include fatty fish, such as salmon and sardines, along with walnuts, flaxseed and chia seeds.
Some research also shows that omega-3 fatty acids can help protect your skin from the sun's damaging UV rays. A small January 2013 study in The American Journal of Clinical Nutrition suggests that taking omega-3 fatty acid supplements may help prevent photoimmunosuppression — the immunosuppressive properties of UV radiation — in human skin.
Also, omega-3s may help protect skin from non-melanoma skin cancers in people at high risk, a February 2016 study in the Journal of Clinical Medicine suggests. Goodson says that you typically need a supplement if you cut out a whole food group from your diet.
So if you don't like eating fish or nuts, you should consider taking an omega-3 fatty acid supplement. Just be sure to talk to your doctor before introducing supplements to your routine.
Read more: 5 Omega-3-Packed Recipes That Aren't Fish
2. A Pale Complexion
A sallow, unhealthily pale complexion may signal that something is going on with your iron levels. "Iron deficiency causes red blood cells to be smaller, fewer and filled with less hemoglobin, which makes them less red," says Kaleigh McMordie, RDN, a registered dietitian in Lubbock, Texas, tells LIVESTRONG.com.
People who are anemic or have an iron deficiency are more likely to have pale or yellow "sallow" skin because of the lower amounts of oxygen being delivered throughout the body, according to the American Society of Hematology. You might notice paleness in the linings of your eyelids and your mucus membranes (for instance, the tissues inside your mouth).
In fact, angular cheilitis, a condition characterized by fissures, cracking, scaling and crusting at the corners of the mouth, has been linked to an iron deficiency, according to a 2019 report in Color of Atlas of Oral and Maxillofacial Diseases.
Iron deficiencies need to be checked out by a doctor, but you can increase your iron intake naturally with dark leafy greens, grass-fed beef, lentils and fortified cereals and breads.
3. Cracked, Sore Lips
Need the occasional swipe of lip balm? Not an issue. In addition to an iron deficiency, seriously cracked and sore lips might indicate you have riboflavin (aka vitamin B2) deficiency.
While a riboflavin deficiency is rare, the National Institutes of Health (NIH) reports that some of the common signs of this deficiency include hair loss, lesions in the mouth and tongue and swollen, cracked lips.
"A riboflavin deficiency can cause cracking at the corners of the mouth and dryness around the outside of the lips," McMordie says. "It will usually be accompanied by a swollen, dark-red tongue and swollen mouth," she says.
Riboflavin deficiency can become more serious if it's left untreated. It can sometimes cause nerve damage that can lead to tingling in your fingers or toes. A small March 2016 study in the Journal of Inherited Metabolic Disease showed that patients with riboflavin deficiency reported issues with neuropathy.
Make sure to get these symptoms checked out as soon as possible to address the deficiency in its earliest stages. And, in the meantime, include more riboflavin in your diet by eating fortified cereal and oatmeal, almonds, salmon, broccoli, cheese and eggs.
The NIH recommends that women age 19 or older get at least 1.1 milligrams of riboflavin daily and men 1.3 milligrams. Pregnant women should get at least 1.4 milligrams daily, and if breastfeeding, 1.6 milligrams.
4. Stubborn Acne
While no single food can unilaterally cause acne (old rumors about chocolate and pizza causing breakouts have been thoroughly debunked), some nutrient deficiencies might make breakouts more frequent or more severe.
Omega-3 fatty acids have powerful anti-inflammatory properties, explains Colleen S. Bucher, RD, LDN, a dietitian based in Greenville, North Carolina. If you're lacking omega-3s, you might notice more inflammation overall, which can manifest as acne. Omega-3s' role in maintaining your skin's lipid barrier comes into play, too.
Your skin's natural oils have antimicrobial properties, and an omega-3 fatty acid deficiency that disrupts your lipid barrier may let acne-causing bacteria in.
In fact, people with mild to moderate acne who were put on omega-3 fatty acid supplements for 10 weeks saw improvements in their skin, per a September 2014 study in Acta Dermato Venereologica. And fish oil supplementation may help improve the overall severity of acne in people with moderate to severe acne (but not in those with mild acne), a December 2012 study in Lipids in Health and Disease suggests.
Read more: 10 Recipes for Glowing, Healthy Skin
5. Wounds That Just Won't Heal
Cuts and scrapes don't generally heal overnight, but missing nutrients in your diet can mean that even the tiniest razor cut seems to stick around forever.
Slow wound healing might signal that you need more protein in your diet. Protein is essential for building and repairing tissue. "Aim for 20 to 30 grams of protein at each meal," Franckowiak says, "and 10 to 15 grams of protein with each snack." Drink a glass of milk with breakfast, add beans to your salads or top your apples with peanut butter for some extra protein.
You should also eat plenty of fruits and veggies for vitamin C because low levels of this nutrient can slow healing (and, in severe cases, even reopen old wounds). In fact, vitamin C, also known as ascorbic acid, plays a big role in different stages of wound healing by contributing to the synthesis of collagen, a December 2013 review in the British Journal of Community Nursing demonstrates. Strawberries, red peppers and grapefruit are some of the best sources.
6. Bleeding Gums
For most people, a little blood on your toothbrush most likely means you need to floss and brush your teeth more often. But if you're a devoted flosser and your gums start bleeding for no apparent reason, you might be dealing with a vitamin K deficiency.
"Vitamin K is best known for its role in helping blood clot, or coagulate," Franckowiak says. It sets off a cascade that activates pro-clotting factors in your blood, which help you stop bleeding after a cut and also prevent spontaneous bleeding from delicate tissues like your gums.
There are two different types of vitamin K: K1 and K2. Vitamin K1 (aka phylloquinone) can be found mainly in leafy greens and cruciferous vegetables, while vitamin K2 (aka menaquinone) is bacteria produced in the gut. You can also get vitamin K2 from fermented foods, cheese, natto, meat, dairy and eggs, according to the NIH.
Enjoy your leafy greens with some healthy fats, like avocado, since vitamin K is fat-soluble.
Vitamin K deficiency is pretty rare, so check with your doctor and dentist to investigate the cause of your bleeding. Vitamin K deficiency is more common in babies because their bodies store very small amounts of the nutrient, but it can also happen in adults who take certain medications that can interfere with the absorption of vitamin K, according to the Centers for Disease Control and Prevention (CDC).
Read more: What Happens When You Get Too Much Vitamin K?
7. Brittle Nails
If you're constantly dealing with painful hangnails and nail breaks, your diet might be low in biotin. Biotin, also known as vitamin B7, nourishes your nails' growth plates, Bucher says. Disrupting your growth plates, not surprisingly, leads to irregular growth, instead of the thick, strong nails you'd like.
Clinical trials suggest that biotin supplementation help improve the firmness, hardness and thickness of brittle nails, a June 2018 review in the Journal of Dermatological Treatment shows. However, most research shows that biotin supplementation is often unncessary.
An August 2019 study in the Journal of the American Academy of Dermatology surveyed 152 participants who take biotin supplements for their hair and nail issues, but more than half of them reported no improvements with their conditions.
This study demonstrates that biotin supplementation may not be as effective for normal nail or hair growth as it is for people with biotin deficiencies or conditions that cause nail deformities. And because biotin is water-soluble, your body doesn't store any excess you might get from supplements.
Still, it's important to note that biotin deficiency is rare. Pregnant and breastfeeding women are at risk the most for biotin deficiency because they need more of this important nutrient for their baby's growth. The NIH reports that at least one-third of pregnant women develop marginal biotin deficiency despite eating a healthy intake of the nutrient, so taking a supplement might be helpful.
In the meantime, you can start getting more of this B vitamin in your diet by simply eating more eggs, cheese, nuts and seeds, fish and organ meats and certain vegetables, such as cauliflower and sweet potatoes.
Read more: Can a Person Take Too Much Biotin?
8. Misshapen or Discolored Nails
While weak nails are annoying, other nutrient deficiencies can make your nails look a little, well, weird.
Low iron levels can lead to whitened or ridged nails, explains Bucher, and can even cause concave and spoon-like nails. A biotin deficiency ups your risk of fungal infections that can cause ridging and discoloration, while a vitamin B12 deficiency can make your nails take on a brownish hue.
See a doctor if you're noticing abnormalities in your nails; you might need medical treatment to clear an infection or correct the nutritional deficiency.
9. Thinning Hair
How well you eat ends up reflected in the health of your hair. While losing some strands is normal (we lose between 50 and 100 hairs daily), noticeable thinning of your hair may not be.
"Protein and vitamin C deficiencies can cause thinning or brittle hair and hair that falls out easily," McMordie says. That's because vitamin C helps you make collagen — one of the building blocks of healthy hair and a strong hair follicle — while protein supplies amino acids for collagen (and other protein) synthesis.
Biotin might also play a role: An August 2017 review in Skin Appendage Disorders shows that clinical trials with biotin supplementation may help improve hair growth in people with certain health conditions that may cause hair thinning or loss, but more research is needed to show the efficacy of supplements in healthy people.
Read more: Are Collagen Supplements Safe?
10. Premature Graying
On top of changing your hair texture, certain nutrient deficiencies can make you go gray.
Copper helps you create melanin, one of the pigments that gives your hair its color. Low copper levels — or an underlying medical issue that prevents you from metabolizing copper properly — can turn your hair gray, McMordie says.
In fact, being low in copper may play a role in premature graying, an April 2012 study in Biological Trace Element Research suggests. And low levels of iron, vitamin B12 and HDL cholesterol (the good cholesterol) are associated with premature graying, a January 2016 study in the International Journal of Trichology suggests. But more research is needed to solidify both of these links.
- The American Journal of Clinical Nutrition: "Randomized Controlled Trial of Oral Omega-3 PUFA in Solar-Simulated Radiation-Induced Suppression of Human Cutaneous Immune Responses"
- Journal of Clinical Medicine: "Potential Benefits of Omega-3 Fatty Acids in Non-Melanoma Skin Cancer"
- The American Society of Hematology: "Iron-Deficiency Anemia"
- The Color of Atlas of Oran and Maxillofacial Diseases: Angular Cheilitis"
- National Institutes of Health: "Riboflavin"
- Journal of Inherited Metabolic Disease: "Clinical Presentation and Outcome of Riboflavin Transporter Deficiency: Mini Review After Five Years of Experience"
- Acta Dermato Venereologica: "Effect of Dietary Supplementation With Omega-3 Fatty Acid and Gamma-linolenic Acid on Acne Vulgaris: A Randomized, Double-Blind, Controlled Trial"
- Lipids in Health and Disease: "Effects of Fish Oil Supplementation on Inflammatory Acne"
- British Journal of Community Nursing: "Vitamin C: A Wound Healing Perspective"
- National Institutes of Health: Vitamin K
- Centers for Disease Control and Prevention: "What Is Vitamin K Deficiency Bleeding?"
- Journal of Dermatological Treatment: "Biotin for Treatment of Nail Disease: What Is the Evidence?"
- Journal of the American Academy of Dermatology: "Assessment of Biotin Supplementation Among Patients in an Outpatient Dermatology Clinic"
- National Institutes of Health: "Biotin"
- Skin Appendage Disorders: "A Review of the Use of Biotin for Hair Loss"
- Biological Trace Element Research: Serum, Iron, Zinc, and Copper Concentration in Premature Graying of Hair"
- International Journal of Trichology: "Factors Associated With Premature Hair Graying in a Young Indian Population"