Why You Might Be Losing Your Hair - Ask a Nutritionist

February 1, 2024

In this first of a special two-part episode of Ask a Nutritionist, Brandy addresses common concerns about hair loss, and explores a few reasons why one might experience thinning hair or hair loss.

Learn the important nutritional needs your body has for maintaining healthy hair, and how diet, lifestyle, and health conditions can impact hair health.

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BRANDY: Hello, and welcome to Dishing Up Nutrition's “Ask a Nutritionist”. My name is Brandy Buro, and I'm a Registered and Licensed Dietitian here at Nutritional Weight and Wellness. We are thrilled to be celebrating 20 years on air discussing the connection between what you eat and how you feel, all while sharing practical real life solutions for healthier living through balanced nutrition. Thank you all so much for your support and listenership over all of these years.

Now let's get started with today's question. I'm actually going to answer two questions today, both related to hair loss. And these questions came from our Dishing Up Nutrition listeners. So our first question is, “I'm 60 and I've noticed thinning hair on my head and my eyebrows. And my leg hair has stopped growing almost entirely. I'm wondering what might cause this and if or how it might be addressed nutritionally.”

And our second question is, “What are the best vitamins or supplements to promote hair growth? Are there any foods to focus on that can help? I've been losing a lot of hair since getting COVID a few years back.”

So these are both great questions and I think together they cover the full spectrum of the topic of hair health. Why might you lose hair and what can you do to support hair growth through food and nutrition? And hair loss is so frustrating, so I'm sure many of you are really wanting the answers to these questions.

Determining the root cause of hair loss

It's a big part of our self expression and our confidence, so when you lose that, it can be very frustrating. And there are so many reasons somebody might experience hair loss. And really the best way to support hair growth will usually depend on the root cause of hair loss.

So when I'm with a client that has these concerns, I ask them a lot of questions about their lifestyle, their health history, their eating habits, and try to pick up on other clues to zone in on the likely cause of their hair loss. That way I can give them a nutrition plan that actually works.

So as I was preparing for this episode today, I realized there's a lot of information to cover here. So I'm going to approach this a little differently. I'm going to split this up into two parts. And today I want to review some of the most common causes of hair loss and give you a few lab tests that you can request in order to help identify the root cause of your hair loss.

And then in part two, which will air next week, I'll dive a little deeper into the nutrition strategies and the key supplements to promote hair growth.

Protein is an essential nutrient for healthy hair

So let's begin by reviewing some of the common causes of hair loss. From a nutritional standpoint, we have to think about nutrient deficiencies first. Protein is an essential nutrient for healthy hair. Protein is what's going to provide the building blocks of hair. Protein provides the amino acids, which are those little building blocks for all sorts of materials in the body.

It helps build our organs, our muscles, our bones, even hormones, and the list goes on and on. So if you are not eating enough protein, your body is going to start prioritizing where those amino acids go. Your vital organs, like your heart and lungs, are going to get kind of first dibs on that protein. Hair is not absolutely necessary for survival, so hair will receive that benefit from protein only if those essential functions are met first.

So, eating enough protein is very important. Protein is also going to give you some crucial vitamins and minerals that support hair health. So, under eating protein may actually set you up for vitamin and mineral deficiencies that contribute to hair loss. Iron, vitamin B12, and zinc are all important players in hair growth.

And they can all be found in high quality animal based proteins like meat, eggs and fish, and all of these animal based proteins, meat, eggs and fish, they're also great sources of other B vitamins, particularly, B7, which we know more commonly as biotin.

And I think all of us understand that there's a connection between biotin and hair health because biotin is found in so many over the counter hair health supplements. And it's true, biotin plays a role in building keratin, which is the main protein fiber of hair.

Healthy fat is important for hair health

So other than protein, we also have to think about fat. Fat is another nutrient that's very important for hair health. And those low fat diets or not eating enough of certain types of fat can lead to dry and brittle hair that's more likely to break off and shed. Because fat actually helps hydrate the hair, makes it very soft, supple, and pliable.

Incorporate omega-3 fats for hair health

Unfortunately, many diet plans restrict fat. And oftentimes it results in deficiencies of essential fatty acids. Essential fatty acids are fats that can only be acquired through the food that we eat. And a specific type of essential fat called omega-3 fatty acids can actually help reduce inflammation in the body, even at the hair follicle.

So we want to be sure to get plenty of omega-3 fatty acids and other essential fatty acids so that we can keep inflammation low in the body. Some good sources of essential fats are fatty fish and fish oil, flax seeds, chia seeds, and even eggs, pasture raised eggs.

Vitamin E and D are helpful for hair growth

So those low fat diets are also limiting your ability to absorb fat soluble vitamins like vitamin E and vitamin D. Vitamin E is very important for hair growth because it's in part responsible for helping build those tiny blood vessels that blood flows through in order to get nutrients and oxygen to the hair follicle.

And research is showing that a deficiency in vitamin D is related to hair loss. So, I think we all know vitamin D is important for overall health, but there is a role that it plays in hair too. So we want to get enough fat so that we can absorb these important vitamins. So you're probably getting the sense by now that under eating, as you may in calorie restricted diets, can all lead to those nutrient deficiencies that I just described.

What else can lead to a nutrient poor diet?

But from another perspective, eating a diet that's very high in processed foods, which is very nutrient poor, can cause those same issues. I also want to point out that vegetarian and vegan diets can make it very challenging to consume enough protein along with the nutrients that come with it: iron and vitamin B12.

Other than nutrient deficiencies, under eating may also trigger stress in the body. And that stress can lead to hair loss. I see this a lot in those crash diets, or very restrictive eating patterns where maybe there's the promise of quick weight loss, but the end result is still under eating and you could be tricking your body into thinking that it's starving.

And actually, you probably are starving. And that is signaling a stress response. You may lose some weight, but a lot of that weight is going to come from your muscle. It's literally borrowing protein from your muscle in order to preserve vital organs that keep you alive. And again, hair is not quite essential for survival, so resources are going to be diverted and hair growth is put on the back burner. So those crash diets, restrictive eating, or even like weight loss surgeries can all cause hair loss in that regard.

Poor gut health can lead to nutrient deficiencies

So other than simply not consuming enough of these key nutrients, another aspect of health that can lead to nutrient deficiencies is poor gut health. And that's what I want to talk about next: how poor gut health can cause nutrient deficiencies and hair loss. So let's start in the stomach. Apart from chewing, this is where a lot of the mechanical breakdown of food happens. So that you can absorb the nutrients from those foods further along in the digestive tract. One thing that can compromise this process is having too little stomach acid.

And that can lead to poor absorption of protein, iron, and vitamin B12. So some signs that you could have low stomach acid are heartburn or acid reflux. Or maybe you get very full after you start eating a meal, especially if it is a protein rich meal. Or something else to watch for is seeing pieces of food in your stool.

And that's just a sign that you're not adequately breaking down that food. And your stomach acid levels tend to decrease as we age, but there are a few things that could accelerate that decline and make that much worse. Alcohol is a big one. Certain medications like heartburn medication and acid blockers.

I mean their function is to lower your stomach acid. So if you are taking those medications on a regular basis your stomach acid is just going to be suppressed day in and day out and that issue of low stomach acid is just going to get worse and worse and that is going to compromise your digestion and possibly lead to nutrient deficiencies.

What can cause damage to the intestinal lining?

Nutrient deficiencies can also be a consequence of damaged intestinal cells. So your intestinal cells, especially in the small intestine, are responsible for absorbing nutrients. If those cells become damaged, you can't absorb the good things from your food. A few things that can lead to damage to the intestinal cells and the intestinal lining include alcohol, once again, but also processed foods, sugar, pesticides in our food, toxins in our environment, and medications like pain medication.

That can all cause damage to the intestinal lining. There are specific foods that could also be very irritating to those intestinal cells. Sources of gluten can be damaging to certain people and lead to nutrient deficiencies, and it can also trigger a lot of inflammation in the body. If you have a damaged gut, this can actually lead not only to nutrient deficiencies and absorption issues, but it can also trigger an overactive immune response.

Because 80 percent of our immune function resides in the gut. So when your gut lining is damaged and irritated, it can cause your immune system to kick into gear, triggering a lot of inflammation in the body. So if your immune system is constantly triggered because of poor gut health, you could be at risk for developing an autoimmune disease.

Autoimmune disease: a possible cause of hair loss

That's when your immune system gets confused and it starts to attack your own body. And that leads me into the next possible cause of hair loss, autoimmune diseases. Often times hair loss can be a sign that you have developed an autoimmune disease. For example, thinning eyebrows, especially the outer third of the eyebrow, could be a sign of hypothyroidism.

So I wanted to point that out because it might be relevant to one of our listeners that wrote in with one of the questions today. And most cases of hypothyroidism are an autoimmune condition called Hashimoto's disease. Another autoimmune condition called alopecia areata. can result in hair loss. It usually shows up as little patches of hair loss, usually on the scalp, but that hair loss can happen anywhere on the body. Psoriasis and lupus are two other autoimmune conditions, where you might see hair loss. And sort of connected to this topic of autoimmune conditions is medications used to treat them.

Certain medications and stress can cause hair loss

Medications like steroids and immune suppressants can sometimes cause hair loss. Stress is another common cause of hair loss. And I believe stress may have been related to the hair loss experienced by one of our listeners who said they lost a lot of hair after having COVID.

And it's true, COVID or any other severe infection, especially if you had a fever, you could cause enough stress in the body to trigger hair loss. Any big stressful event can have the same effect. This includes something like major surgery, even emotional trauma or physical trauma. I often see this after someone gives birth or the extreme crash diets that we just talked about.

So there's a term for this type of hair loss after a stressful event. They call it telogen effluvium. It's kind of a mouthful. But this is basically when that stressful event abruptly stops the growing phase of hair and pushes it into the resting phase, or the telogen phase. And that phase lasts for only about three to four months before it dies your hair sheds and the process of growing starts again.

So it's sometimes kind of difficult to pinpoint the cause of hair loss if it's related to stress because the hair shedding will usually happen three or four months after the stressful event happens. And often times hair will regrow after that stressful event passes.

But if that stressor is still part of your life, you may have a challenging time regrowing that hair. So the stress needs to be effectively managed before the hair will start to grow back. And it may take a few months to see that change. But if you're under chronic stress or long-term stress, something else that can happen is it may start to toy with your hormone balance.

Because when we're under chronic stress, our cortisol levels will start to become very high. And if your cortisol levels remain high for a long time, that can impact the balance of hormones elsewhere in your body. So this kind of triggers some of the hormonal imbalances that can lead to hair loss.

Hormonal imbalances: common cause of hair loss

This brings me to another common cause of hair loss, hormonal imbalances. hormonal imbalances can happen in chronic states of stress, but they are also very common in various stages of a woman's lifetime. So we experience major shifts in our hormone levels, of course when we enter puberty, but also when we enter perimenopause and menopause, pregnancy, after giving birth, or going on or off hormonal birth control.

And our hair growth relies on a delicate balance between progesterone and estrogen, but also types of hormones called androgens, which include testosterone and dihydrotestosterone, or DHT for short. And I think we often hear about testosterone in the context of men's health, but women also need a certain amount of testosterone for good health as well.

And there's a specific type of hair loss called androgenic alopecia, which is actually caused by excess levels of androgens, particularly DHT, which is made from testosterone, but it's much more potent than testosterone. And our levels of DHT tend to increase as we age, which can cause our hair follicles to shrink, making our hair much finer, more likely to fall out.

And this is more common in women that are entering perimenopause and menopause because our progesterone and our estrogen is shifting very rapidly. This is also something that you might see in women experiencing, or women that have been diagnosed with a condition called PCOS or polycystic ovarian syndrome.

Something else that can increase your risk for developing this type of hair loss, androgenic alopecia, is insulin resistance. And we've talked a lot about insulin resistance on our show but just as a brief recap, insulin resistance is when you need a higher and higher amount of a hormone called insulin to help manage your blood sugar.

And this is a condition that will develop over many years of having chronically high blood sugar levels. And when your blood sugar is high, your insulin levels are high. And when your insulin levels are high, your body tends to produce more testosterone. So the potential for it to convert into that more potent testosterone, DHT, is increased.

So that's one aspect of, hormone balance and hair loss connected to insulin resistance. One other aspect of insulin resistance that can lead to hair loss is if left untreated, you may develop diabetes, which is a more advanced form of insulin resistance. And if your diabetes is not well controlled, it can reduce blood flow to those small, tiny blood vessels.

And remember we talked about small, tiny blood vessels supplying our hair follicles with nutrients. So if you are insulin resistant and have diabetes, the potential for you to get those nutrients to those hair follicles diminishes. And that kind of wraps up, some of the more common causes for hair loss.

Recap of possible hair loss causes

We just covered nutrient deficiencies, poor gut health, autoimmune diseases, stress, hormonal imbalances, and insulin resistance. So it's time for a quick break, but when we return, I'm going to share with you a few lab tests that you can request at your doctor's office to help identify the possible cause of hair loss.


Welcome back to Dishing Up Nutrition's “Ask a Nutritionist”. Now that we've covered some of the major causes of hair loss, you're probably wondering, how do I determine what, if any of these are an issue for me? Do any of these concerns apply to me? Well, I'm going to share with you some helpful tests that you can request at your next doctor's visit to help determine any possible underlying causes of your hair loss.

Tests that can help determine possible underlying causes of hair loss

So going back to nutrient deficiencies, I would first want to rule out anemia. Anemia can indicate low iron, low vitamin B12, low protein intake. It can also indicate an absorption issue. But either way, if you are anemic, that means that you are not getting enough oxygen to your hair follicles.

So to test for anemia, I would request a complete blood count. This is pretty routine and most physical lab work that you would have done, but you might just want to ask for it anyway to be sure that it's done. I would also ask to get your iron levels or your ferritin checked, along with your vitamin B12 level.

So if your iron or your B12 levels are low, you may need to supplement for a while. And again, those low levels may also indicate an absorption issue, especially if you feel like you are eating high quality animal based protein sources several times a day. I also recommend that you get your vitamin D level checked.

I think we all understand vitamin D is very important, but in the context of hair, vitamin D plays a big role in regulating inflammation in the body. And if you are experiencing inflammation even at the hair follicle level, that can cause some issues with hair growth. Low vitamin D can also be a sign of an autoimmune condition. So best to get that checked. You want to see your levels somewhere between 60 and 80 nanograms per milliliter. If you are lower than 60 or 50 you may want to supplement.

The next couple of tests I want to talk about are geared towards identifying whether or not you are experiencing insulin resistance. We want to identify and treat insulin resistance early, so that we can rebalance hormones, but also prevent the more advanced stage of diabetes and related complications like poor blood flow and neuropathy. So to test for insulin resistance, there's a few things I like to look at. Get your fasting blood sugar along with your A1C, which are both pretty routine.

But I would also tack on your fasting insulin. And your fasting insulin is going to complete that picture of insulin resistance. And you will probably have to request fasting insulin. That is not something that is done routinely in a doctor's office visit, but ask for it and you should be able to figure that out. We help clients interpret these results all the time.

Hormone levels, as we've learned, can also cause issues with hair. So for women, I would recommend testing total testosterone and free testosterone in order to help identify if androgen excess is an issue.

And last but not least, in order to help identify a potential autoimmune condition, I would test your thyroid first and check if there is a possibility of hypothyroid or Hashimoto's disease. And I would request a full thyroid panel and be very specific in asking for the full thyroid panel, which includes TSH, free T3, free T4, and the thyroid antibodies.

And this is another area that, it can be very helpful to have the help of a registered dietitian to help you interpret what this all means and what sort of nutrition or dietary guidance can help you.

So I hope that this was helpful information for all of you out there concerned about hair loss. Stay tuned for part two next week where I'll dive a little deeper into the nutrition strategies and talk about some therapeutic supplements to support hair growth and hair health.

Thank you all so much for listening to Dishing Up Nutrition's “Ask a Nutritionist”. If you found this episode helpful, be sure to leave us a rating or review on your favorite podcast app so we can help reach even more people discover the connection between what they eat and how they feel. And if you have a nutrition question that you'd like us to answer, please join our private Dishing Up Nutrition Facebook group.

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