Why most of us are nutrient deficient - and what to do about it

The vast majority of us are suffering from nutrient deficiency! Whether we like it or not, nutrient deficiency has a vast impact on our quality of life, increases our risk of chronic disease, and shortens our life span. This is not something you will likely hear from your doctor, or have seen much about in the news. Yet, nutrient deficiency is well established in the scientific literature, and recent statistics suggest it affects almost 100% of the population - at least to some degree.


Nutrient deficiency is relatively easy to treat and doesn’t require a team of physicians, expensive lab tests, or medications with side effects. When nutrient deficiencies are addressed, most people experience improvements in all physical areas, like more energy, better sleep, sharper minds, clearer skin, smoother digestion, and better physical performance and recovery. In short, you could say that treating nutrient deficiencies slows and even reverses the ageing process! 

In this article, I'll explain:

  • Why micronutrients - vitamins, minerals, and other compounds - are so critical to our health.
  • Why most of us don’t get enough of them.
  • Why a healthy diet should always be the starting place for restoring optimal nutrient status.
  • Why we can no longer meet all of our nutrient needs through food alone.
  • How 'smart supplementation' can close the modern nutrient gaps, improve our health, protect us from disease, and extend our life span.

Our body needs about 40 different essential nutrients (vitamins, minerals, antioxidants) to stay healthy. We should aim to eat nutrient-dense foods on a daily basis. Failure to do so can lead to deficiencies of micronutrients which contributes to all types of chronic disease and ageing. For example:

  • Vitamin C deficiency can lead to poor immunity, chronic fatigue and abnormal blood pressure.
  • Vitamin D deficiency increases the risk of all types of autoimmunity, cancer and heart disease.
  • Magnesium deficiency is linked to insomnia, anxiety, depression, diabetes, and heart disease.
  • Choline deficiency promotes cognitive issues and DNA damage.
  • Vitamin B12 deficiency is linked to neurodegenerative disease.
  • Folate insufficiency is linked to birth defects and high homocysteine levels that can lead to DNA damage and certain types of cancer. 

Until recently, we thought of micronutrients as necessary for survival and protection against severe illness. It is now established that micronutrients are necessary for optimal health.

While mild nutrient deficiencies aren’t enough to cause overt clinical symptoms, they still contribute significantly to the ageing process and the diseases of ageing.

And this is what makes optimising nutrient status so tricky - and so important. Today we are not talking about full-blown nutrient deficiencies that would cause acute diseases like rickets, scurvy, beriberi, and pellagra. We are talking about nutrient intake that falls short of the Recommended Dietary Allowance (RDA), or maybe even between the RDA and the optimal amount - which is often significantly higher than the RDA. Most people aren’t aware they are nutrient deficient. Here’s why. 

First, it’s difficult to know if you’re falling short on nutrients from symptoms alone. You may not develop any symptoms in the short term or, if you do, they’ll likely be symptoms like low energy, brain fog, poor sleep, and digestive or skin issues - exactly the type of mild symptoms that almost everyone today experiences. 

Second, most doctors and healthcare providers don’t test routinely for nutrient deficiencies, perhaps outside of maybe iron and vitamin D, plus they are looking for normal, rather than optimal levels. For folate, you need to look into active folate levels. For B12, you need to look at active B12 levels, most diagnostic tests do not test for the latter. While functional medicine practitioners and nutritional therapists run these tests, insurance doesn’t cover these tests.

Third, many people believe that nutrient deficiencies only affect people in the developing world. Sadly, nothing could be further from the truth. 

Nutrient deficiency statistics are often based on the RDA. The RDA is simply the minimum amount of a nutrient that we need. It was developed during World War II! It is not the amount that we require for optimal health and longevity. The RDA does not consider health status. People with chronic health conditions like obesity, diabetes, and gastrointestinal disorders have both higher demand for and decreased absorption of nutrients. For example, people with obesity do not convert sunlight to vitamin D in their skin or absorb vitamin D from supplements well. They should hence consume significantly higher doses of vitamin D. 

Another problem with the RDA is that it doesn’t consider bioavailability. The amount of bioavailable nutrients in food is almost always lower than the amount of nutrients the food contains. For example, the bioavailability of calcium from spinach is only 5%.

The form that nutrients take significantly impacts their bioavailability in the body. For example, heme iron, a form of iron found only in animal products such as meat and poultry, is far more bioavailable than nonheme iron, found in plant foods.

The absorption of nutrients is also affected by the presence (or lack) of other nutrients. Iron can only enter cells in the presence of adequate copper. Magnesium is required to activate vitamin D. Vitamin C enhances the absorption of iron in the digestive tract. So, even if you’re getting enough vitamin D from sun exposure or supplements, you’d still exhibit vitamin D deficiency if you aren’t also getting enough magnesium (which is needed to activate vitamin D).

Nutrient inhibitors and anti-nutrients reduce the bioavailability of nutrients in foods. Phytate, an anti-nutrient found in large amounts in grains and legumes, binds to calcium, iron, and zinc, making them unavailable for absorption. This is why RDA underestimates the amount of nutrients that we need for optimal health, in most cases.

Why are nutrient deficiencies so common?

Our intake of calories is steadily rising over the past 50 years. Lots of calories come from processed foods like soda, desserts, pizza, bread, and fast foods. These foods are virtually devoid of the vitamins, minerals, and other compounds that we need to maintain our health and vitality and prevent disease. You could say that we are well-fed but undernourished!

Over the past several decades, we have disrupted the microbiome of the soil with chemical fertilisers, herbicides, and pesticides. This has interfered with the ability of plants to extract nutrients from the soil, which, in turn, has decreased the amount of nutrients we get from eating plants (or from eating animals that have eaten plants). One study found that we’d have to eat eight oranges today to get the same amount of nutrients that our grandparents would have gotten from eating a single orange!

Toxins, which have become ubiquitous in our food supply, decrease nutrient availability in numerous ways. For example, glyphosate interferes with our gut bacteria’s ability to produce and absorb several different nutrients, including folate, glycine, vitamin E, and vitamin K. Heavy metals like mercury, cadmium, and arsenic decrease nutrient absorption too. 

Most of the produce sold at large supermarket chains is grown hundreds - if not thousands - of miles away. The problem with this is that food starts to change as soon as it’s harvested, and its nutrient content begins to deteriorate. 

Many common OTC and prescription medications decrease nutrient absorption. Metformin, a drug that is used to lower blood sugar in people with diabetes and PCOS, is known to cause vitamin B12 deficiency. Proton pump inhibitors (PPIs), which are prescribed for acid reflux, increase the risk of vitamin and mineral deficiencies - including vitamin B12, vitamin C, calcium, iron, and magnesium. Oral contraceptives have been shown to deplete the body of folate, vitamins B2, B6, B12, C, and E, and magnesium, selenium, and zinc. 

An increase in chronic disease - chronic disease affects nutrient status in two ways: it decreases nutrient absorption; and increases the demand for nutrients. People with autoimmune thyroid disorders may need additional selenium compared to those with normal thyroid function. Digestive disorders like small intestinal bacterial overgrowth (SIBO) interfere with the absorption of nutrients like vitamin B12. 

How to restore optimal nutrient levels

A nutrient-dense diet should always be the starting place for protecting against nutrient deficiencies. Whole foods contain a wide range of vitamins, minerals, and phytonutrients that work synergistically to support our health. Some of the most nutrient-dense foods are:

  • organ meats (liver, spleen, kidney, and heart)
  • fish
  • beef
  • eggs
  • full-fat dairy
  • herbs and spices
  • dark green leafy vegetables
  • crustaceans

In addition, over the last few years, many nonessential nutrients have been identified that are important to our health, even if they aren’t strictly essential. These include carotenoids, polyphenols, flavonoids, lignans and fiber, most of which are found in plant foods like fruits and vegetables. 

If we want to maximise our intake of both essential vitamins and minerals and phytonutrients, we need to consume both plant and animal foods. But how much of the diet should come from animals, and how much from plants? The answer to this question will vary based on individual needs. About two-thirds to three-quarters of the plate should be plant foods, though!

Both plant and animal foods play an important role in our diets because they are rich in different nutrients. While plant foods are rich in vitamin C, carotenoids, polyphenols, flavonoids, lignans, plant sterols, isothiocyanates and indoles, and prebiotic fibers, animal foods are rich in vitamin B12, heme iron, zinc, preformed vitamin A (retinol), high-quality protein, creatine, taurine, carnitine, collagen, selenium, vitamin K2, vitamin D, DHA, EPA, Conjugated linoleic acid (CLA).

Why diet is no longer enough to achieve optimal nutrient status

In a perfect world, we’d be able to meet all of our nutrient needs from food alone. But, due to ultra-processed food, a global, industrial food system, changes in soil quality, toxins like heavy metals and glyphosate, an increase in chronic disease, OTC and prescription medications, this is not possible!

'Smart supplementation' can close the modern nutrient gap so you can feel and perform your best. Hundreds of studies have shown that supplementing with micronutrients can lead to significant improvements in everything from cardiovascular risk markers to anxiety and depression to digestive health to hormone balance.

But of course, not all supplements are created equal. I’m guessing you’ve seen a lot of stories in the media raising the alarm about poor-quality supplements. Many supplements are made with cheap, synthetic ingredients that are difficult for the body to absorb. For example, many products on the market contain synthetic folic acid instead of a natural bioavailable form of folate. Some research suggests that unmetabolized folic acid can increase the risk of cancer!

Many supplements contain too much of the wrong stuff or not enough of the right stuff. For example, multivitamins often contain high doses of calcium and iron. While calcium and iron are essential in the diet, many studies have shown that supplementing with these nutrients at high doses can be harmful. On the flip side, many supplements tend to skimp on critical nutrients we don’t get enough of in the diet, like vitamins C and D. Most products on the market contain 400 IU of vitamin D, which isn’t enough to raise blood levels to the normal range in most people. That’s why it’s so important to choose high-quality products, prescribed by a practitioner you trust.

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

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