In an ideal world, it would be best to get all the nutrients we need from high-quality, wholesome foods, but how realistic is that? With our busy lifestyles, we often don’t take the time to plan and prepare well-balanced, nutritious meals. The Standard American Diet (SAD), characterized by convenience, processed foods, and a focus on taste rather than nutritional content, has exacerbated the ongoing issue of inadequate nutrient intake.(1) However, it is not just these ‘food-like’ products lining the grocery store shelves that are contributing to the problem. According to Studies in the American Journal of Nutrition (ACN) and the American Journal of Agricultural Sciences (AJAS), the nutritional content of many varieties of fruits and vegetables has been in decline for the past 70 years.(2)


Agricultural practices such as intensive farming and the excessive use of synthetic fertilizers have contributed to the deterioration of soil quality, leading to a decrease in vital nutrients such as vitamins and minerals within cultivated crops. Moreover, the emphasis on breeding crops for higher yields and resistance to pests has occasionally inadvertently led to changes in nutrient composition. Simply put, the tomatoes your grandparents or parents ate were nutritionally superior to those cultivated today. 

Given the changing nutritional profile of our staple foods, it becomes essential to understand and identify the nuances of nutrient deficiencies we might be facing. Let’s explore 10 frequent nutrient deficiencies, noting that they are presented without any specific ranking, along with the signs and symptoms to watch out for.

Vitamin C

Vitamin C, also known as ascorbic acid, is a water-soluble essential nutrient crucial for various bodily functions. It acts as an antioxidant, protecting cells from damage caused by free radicals, thus reducing the risk of chronic diseases. Additionally, it plays a vital role in collagen production, supporting skin, blood vessels, and bone health, as well as aiding wound healing. Vitamin C boosts the immune system by facilitating white blood cell production and enhancing its defense against infections. It aids in non-heme iron absorption, which is particularly important for those with plant-based diets. Vitamin C is not synthesized by the body, therefore it must be obtained through dietary sources or supplements.

Signs of Deficiency—Fatigue, weakness, swollen and bleeding gums, joint pain, muscle aches, slow wound healing, dry and rough skin, anemia, bruising easily, and a weakened immune system.

Dietary Sources—Citrus fruits are the most widely recognized source of Vitamin C, however, red bell peppers, guava, kiwi, strawberries, and even broccoli are all excellent sources. The acerola cherry (Barbados cherry) contains the highest amounts of Vitamin C of any food, providing anywhere from 1,500mg to 4,500mg per 100 grams.(3) Eating a wide variety of colourful fruits and vegetables is your best bet.


Iodine is an essential trace element that plays a crucial role in maintaining the health and proper functioning of the human body. It is found in every organ and tissue in the body, and deficiency or insufficiency of iodine in any of these tissues can lead to dysfunction of that tissue. The most well-known role of iodine is its involvement in the production of thyroid hormones. The thyroid gland utilizes iodine to synthesize hormones such as thyroxine (T4) and triiodothyronine (T3). These hormones play a pivotal role in regulating the body’s metabolism, energy production, and the overall functioning of various organs and systems.

Iron Fatigue

Signs of Deficiency—Some common signs of iodine deficiency include an enlarged thyroid gland (known as a goiter), fatigue, weight gain, dry mouth or skin, brittle nails, and thinning hair. Additionally, cognitive issues such as poor concentration and memory problems can arise, especially in pregnant women and infants, as iodine is vital for proper brain development. Severe deficiency may lead to hypothyroidism, characterized by lowered metabolism, cold intolerance, and a general feeling of sluggishness. 

Dietary Sources—While iodized salt stands out as a widely recognized source of iodine, incorporating foods like seafood, seaweed, kelp, spirulina, fish, and dairy products into your diet can provide valuable and diverse sources of this vital trace mineral.

It’s important to be aware that while iodine deficiency is a valid concern, excessive intake of iodine can also yield adverse effects. Overconsumption, particularly through supplements, has the potential to disrupt thyroid function and may contribute to the onset of thyroid disorders.(4)

Vitamin B12

Vitamin B12, also known as cobalamin, is a water-soluble nutrient essential for numerous bodily functions. It plays a pivotal role in red blood cell formation, ensuring efficient oxygen transport throughout the body. B12 is vital for maintaining the protective myelin sheath around nerve fibers, supporting nervous system health. It is involved in DNA synthesis and cell division, fundamental for growth and tissue repair. Furthermore, B12 is key for neurotransmitter synthesis, which impacts mood and cognitive function. By converting the amino acid homocysteine — linked to neurodegenerative diseases — into methionine, B12 helps maintain its balance. Studies indicate that B12 might preserve brain size as we age and defend against oxidative stress, highlighting its role in staving off neurological decline.(5) When choosing supplementation, opt for methylcobalamin as this is a natural, active form of vitamin B12 that is directly available for cellular processes upon ingestion, making it more bioavailable than the synthetic cyanocobalamin. 

Signs of Deficiency—Fatigue, weakness, constipation, loss of appetite, weight loss, brain fog, mood swings, poor memory, or numbness and tingling in the hands and feet. Additionally, some people may experience difficulty maintaining balance, depression, confusion, dementia, and mouth or tongue soreness. Unfortunately, B12 deficiency may not present itself for several years, so by the time you notice symptoms, you may be quite deficient.

Dietary Sources—Vitamin B12 is only found in animal foods–beef and beef liver (grass-fed beef is highly preferable to the grain-fed variety), lamb, snapper, venison, salmon, shrimp, scallops, organic pastured poultry and eggs.

Omega-3 Fatty Acids

Omega-3 fatty acids, comprising of alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) are considered essential as our bodies can’t produce them; they must be sourced from our diet. They’re crucial for brain function, supporting cognitive growth, and potentially lowering the risk of neurodegenerative diseases by ensuring efficient brain cell signaling. Omega-3s are linked to reduced risks of depression and anxiety, possibly due to their anti-inflammatory effects in combating neuroinflammation.(6) Beyond mental health, their anti-inflammatory properties can alleviate symptoms of autoimmune disorders and arthritis, and they promote cardiovascular health by lowering triglycerides, blood pressure, and heart disease risk.(7)

Dry Skin

Signs of Deficiency—Dry and itchy skin, dandruff, brittle hair and nails, poor concentration, fatigue, joint pain, and stiffness. Additionally, some individuals may experience mood swings or feelings of depression, frequent illnesses, problems with vision or eye dryness, or menstrual cramps.

Dietary Sources—Fatty fish, including salmon, mackerel, sardines, herring, and anchovies, flaxseeds and flaxseed oil, chia seeds, walnuts, and hemp seeds.


Magnesium is an essential mineral whose health benefits are often overlooked. This mineral is used by every organ in your body, especially your heart, muscles, bones, and kidneys. Researchers have recently found over 3000 magnesium binding sites on human proteins and have also found it in more than 300 different enzymes in the body.(8) These enzymes are responsible for the creation of ATP (energy), the formation of healthy bones and teeth, the relaxation of blood vessels, the promotion of proper bowel movements, the regulation of blood sugar, and numerous detoxification processes.

In North America, magnesium intakes fall short of dietary recommendations for a large segment of the population. Causes of magnesium deficiency may be related to poor diet, high caffeine or alcohol consumption, hormonal imbalances, exposure to pesticides, and the regular use of diuretics and antibiotics that prohibit the proper absorption of the mineral. 

Signs of Deficiency—Muscle cramps or weakness, fatigue, irregular heart rhythms, numbness or tingling, restless leg syndrome, personality changes like increased irritability or confusion, migraines, and vertigo. 

Dietary Sources—Dark leafy greens such as spinach and Swiss chard; nuts like almonds and cashews; seeds, particularly pumpkin and flaxseeds; whole grains like quinoa and brown rice; legumes, including beans and lentils, avocados, bananas, and dark chocolate.

If you’re considering taking a magnesium supplement, magnesium glycinate and magnesium threonate are among the top choices. Magnesium glycinate is a bonded form of magnesium that is easily absorbed and used by the body, making it great for addressing deficiencies. On the other hand, magnesium threonate is an emerging option that stands out because of its enhanced ability to penetrate the mitochondrial membrane. 

Vitamin D

Vitamin D works through a variety of mechanisms and has been shown to be beneficial for heart health, immune support, osteoporosis/osteopenia, oral health, mood disorders, and inflammation.(9) It also helps regulate calcium in the body, necessary for the maintenance of strong bones. It is a powerful epigenetic regulator, influencing the function of over 2,500 genes. Vitamin D receptors can be found throughout the body, including the gut, prostate, pancreas, and immune system cells. Vitamin D deficiency is particularly common among older individuals, those with darker skin tones, and people who regularly use sunblock or avoid spending time outdoors.

Signs of Deficiency—Bone pain, muscle weakness, frequent infections, fatigue, depression, impaired wound healing, hair loss, decreased calcium absorption, increased risk of chronic diseases, cognitive issues in older adults, unexplained infertility, chronic pain, susceptibility to bone fractures, and growth delays in children.

Dietary Sources—Unfortunately, only a handful of foods contain significant amounts of Vitamin D. These include fatty fish, cod liver oil, egg yolks, and beef liver. Additionally, exposure to sunlight, our best source of Vitamin D, is not always available, given the long winters that dominate the Northern Hemisphere. Therefore, deficiency of Vitamin D is extremely common, and supplementation is recommended. 

Consider getting your Vitamin D levels tested to find out your ideal intake. The best time to get Vitamin D levels tested is at the end of the summer, especially in areas where winters are long when technically your reserves should be replenished.

Vitamin K2

Vitamin K2 is potentially just as vital as vitamin D for maintaining good health. Vitamin K (K1 and K2 forms) is commonly added to vitamin D supplements. This is because vitamins D and K work synergistically to promote optimal bone and arterial health. Vitamin K  is involved in various other functions like tissue repair, cell development, ensuring a healthy pregnancy, and possibly preventing cancer.(10)Both vitamin D and K2 support each other; without one, the other can’t function optimally. Vitamin K helps keep important bone protein, osteocalcin, and carboxylated. Undercarboxylated osteocalcin cannot regulate calcium, causing it to circulate freely in the bloodstream and potentially be deposited in the soft tissues (calcification) such as arterial walls or kidneys.


Signs of Deficiency—Bruising easily, bone loss and fractures, calcification of blood vessels, tooth decay, a weakened immune system, growth disturbances in children, and complications during pregnancy.

Dietary Sources—Natto, a traditional Japanese dish made from fermented soybeans, is one of the richest sources of vitamin K2, followed by grass-fed dairy products, egg yolks from free-range chickens, grass-fed meat, chicken liver, sauerkraut, other fermented vegetables, fish eggs, and fatty fish like mackerel, salmon, and sardines.


Choline, an essential nutrient often grouped with B vitamins, serves as a foundational element for cell membrane structure, contributing to the integrity and fluidity of cells throughout the body. It plays a critical role in neurotransmitter synthesis, acting as a precursor to acetylcholine, which is pivotal for memory, muscle control, and mood regulation. It supports liver function by aiding in the metabolism and transport of fats, and it participates in cellular signaling pathways that influence growth and inflammation. Through its involvement in DNA methylation, choline impacts gene expression, while its contribution to brain health and cognitive function underscores its significance. Especially crucial during pregnancy, choline promotes fetal brain development, mitigates neural tube defect risks, and enhances offspring cognitive abilities. Moreover, choline assists in converting homocysteine to methionine, contributing to cardiovascular wellness.

Signs of Deficiency—Choline deficiency may manifest as memory issues, muscle problems, and difficulty concentrating.fatigue, mood changes, and liver dysfunction. More serious choline deficiency has been linked to the development of non-alcoholic fatty liver disease (NAFLD).(11)

Dietary Sources— Beef liver, wild salmon, chicken, and whole eggs. If you choose eggs, keep the yolk slightly runny to prevent oxidation of the choline. Small amounts of choline are in legumes, tofu, green vegetables, potatoes, nuts, seeds, grains, and fruit. 


Glycine is a non-essential amino acid required for protein synthesis and neurotransmission and aids in forming nucleic acids, bile acids, and creatine. Glycine functions as a neurotransmitter in the central nervous system, contributing to the regulation of brain activity and signaling. It also plays a role in the maintenance of healthy skin, joints, and connective tissues. Glycine offers cellular protection and stress reduction benefits, contributing to improved sleep patterns and the maintenance of gut health. Although traditionally not classified as essential, there’s growing consideration for glycine being designated as “conditionally essential.” This is due to the consistent observation of low glycine levels in individuals with metabolic disorders and non-alcoholic fatty liver disease (NAFLD).(12)

While true glycine deficiency is rare, a diet lacking in protein-rich sources or imbalanced in essential amino acids can lead to reduced glycine intake, especially in individuals with restricted diets. Conditions that affect nutrient absorption, such as certain gastrointestinal disorders, can also hinder the body’s ability to absorb and utilize glycine effectively. Genetic disorders that impair glycine synthesis or conversion, chronic illnesses, infections, high-stress levels, and aging can all increase the body’s demand for glycine, potentially leading to deficiency. Additionally, medications and excessive alcohol consumption can disrupt glycine metabolism.

Signs of Deficiency—Difficulties with concentration, memory problems, mood disturbances, muscle weakness and fatigue, sleep disturbances, joint and connective tissue problems, as well as potential metabolic and digestive issues.

Dietary Sources—Glycine is best found in gelatin-rich foods–bone broth, meats like pork and chicken, tuna and salmon, collagen supplements, legumes such as black beans and soybeans, leafy greens like spinach, and seaweed varieties like spirulina and chlorella.

Coenzyme Q10 (CoQ10)

Coenzyme Q10 (often referred to as CoQ10) is a naturally occurring compound found in every cell of the body. Essential for a variety of physiological functions, CoQ10 plays a crucial role in the production of cellular energy. Within the cells, it’s primarily located in the mitochondria, responsible for generating adenosine triphosphate (ATP), the main energy currency of the cell. Beyond its central role in energy production, CoQ10 also functions as a powerful antioxidant. It helps neutralize harmful free radicals, which are unstable molecules that can damage cells and contribute to aging and various health disorders. This protective role is particularly prominent in cells that are exposed to high oxidative stress, such as those in the heart and the liver. Also known as ubiquinol, the reduced form of CoQ10 shares an identical molecular structure. When CoQ10 undergoes reduction, it acquires two electrons, transforming into ubiquinol. Within your body, this change happens countless times per second within the mitochondria. Ubiquinol’s potential benefits for heart health stem from its antioxidant properties and energy support. Elevated C-reactive protein (CRP) levels signal inflammation and heightened cardiovascular disease risk. Some research suggests ubiquinol supplementation might help reduce CRP levels, potentially promoting heart health. (13)

As the body ages or due to certain conditions, the levels of CoQ10 can decrease, potentially affecting the efficient functioning of cells. Statin drugs, in particular, are known to reduce the liver’s ability to synthesize CoQ10.(14) Considering that more than 25% of Americans are on a statin drug, many may be quite deficient in this vital nutrient. 

Signs of Deficiency—Fatigue, muscle pain, cognitive issues, heart-related problems, gum and oral health issues, migraines, weakened immune system, skin concerns, digestive problems, and sleep disturbances.

Dietary Sources—Organ meats such as heart, liver, and kidney are the richest sources of CoQ10, followed by fatty fish like sardines, mackerel, and salmon, while meats like pork, beef, and chicken, along with whole grains, vegetables like spinach, broccoli, and cauliflower, eggs, soybeans, and nuts and seeds like peanuts and sesame seeds also contribute to dietary CoQ10 intake.

How Do You Know If You Are Deficient? Testing Options To Consider

  1. Blood Serum Test—This test measures the levels of some vitamins and minerals in the liquid portion of the blood called serum. The most common ones to be measured by routine lab work include vitamin D, vitamin B12, iron, and ferritin, however, your annual regular blood work is most likely not comprehensive enough to test for other specific vitamin and mineral deficiencies. More extensive nutrient panels also exist to measure a combination of vitamins, minerals, and antioxidants that can impact health and can be ordered through a functional health practitioner. These include:
  2. Organic Acid Testing—Laboratory tests can precisely measure nutrient deficiencies, helping you understand and address your specific health needs. Organic acid testing (OAT) detects nutritional gaps affecting metabolic processes. Mosaic Diagnostics offers this and tests for mycotoxins, food sensitivities, and yeasts.
  3. Comprehensive Nutritional Profile—Genova Diagnostics, a leading clinical lab, offers the NutrEval® assessment, which analyzes over 125 biomarkers like vitamins, amino acids, and antioxidants from urine and blood samples (see sample report here). They also offer the Metabolomix+ test, a more accessible home test focusing on metabolic needs and oxidative stress markers (see sample report here). It offers a broader metabolic perspective than OAT by including amino acids and oxidative stress markers, but it isn’t as extensive as NutrEval®. Please note that these tests need to be ordered through a licensed healthcare provider but may not be covered through regular health plans. 
  4. OmegaQuant—To ensure that you are getting adequate essential fatty acids, you may want to consider OmegaQuant testing. It is a simple blood test that can be performed by a healthcare provider or at home using a test kit. The test involves drawing a small amount of blood and sending it to a laboratory for analysis. The OmegaQuant test measures the levels of EPA and DHA in your blood, providing you with accurate and precise information about your omega-3 status. The results of the test are typically available within a few days and can be used to inform your dietary and lifestyle choices.

Though there is a cost associated with these tests, their value cannot be overstated when it comes to making informed decisions about your health and nutritional status. 

Overcoming Deficiencies—Supplementation Considerations

If you start taking vitamin supplements after suspecting you’re deficient, it’s important to understand that you shouldn’t expect to see instant results. The time it takes for your body to reach a healthy state again can vary depending on the severity of your deficiency. When your body lacks essential vitamins, it can lead to various symptoms and health issues, and simply taking a supplement won’t immediately reverse these effects. The process of restoring vitamin levels and addressing deficiencies takes time and patience.

The duration it takes for your body to recover from a deficiency depends on multiple factors–the severity of the deficiency, your overall health, your body’s ability to absorb and utilize the supplemented vitamins, and whether any underlying conditions affect your nutrient absorption.

If your deficiency is mild or moderate, and you start taking the appropriate supplements as recommended, you may start noticing improvements in your health in a few weeks. Restoring your vitamin levels to a healthy range may take longer for more severe deficiencies. In some cases, your healthcare provider may prescribe higher doses of supplements to accelerate the replenishment process. Regular monitoring and follow-ups with your healthcare professional are essential to ensure you’re on the right track and to make any necessary adjustments to your supplement regimen.

Combining supplements with a healthy diet and lifestyle is a comprehensive approach to promoting optimal health and addressing deficiencies effectively.

Not All Vitamins Are Created Equal

When buying supplements, it is important to do your research. Good supplements should be whole-food-based, without chemicals, dyes, binders, or fillers. Find a nutraceutical company that is meticulous with its raw material and nutrient selection, one that aims to maximize the stability, absorption, and metabolism of its formulas. Ensure that they offer nutritional supplements that are free of ingredients commonly associated with negative side effects, that are non-GMO sourced, gluten-free, soy-free, and free of any artificial sweeteners or flavours. They must also be in accordance with the GMP regulations by the NSF International.(15) 

As I’ve emphasized before, the ideal scenario is to fulfill all our nutritional needs solely through our diet. However, reality often shows that we might need a boost to bridge certain nutritional gaps. For those seeking a trusted solution, click here to explore high-quality supplements from one of the most reputable companies I endorse.

As with all things health-related, the key lies in being informed, patient, and committed to your well-being. Your body deserves the best, and with the right approach, balanced and vibrant health is within reach.

In-text References

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  1. Sherriff JL, O’Sullivan TA, Properzi C, Oddo JL, Adams LA. Choline, Its Potential Role in Nonalcoholic Fatty Liver Disease, and the Case for Human and Bacterial Genes. Adv Nutr. 2016 Jan 15;7(1):5-13. doi: 10.3945/an.114.007955. PMID: 26773011; PMCID: PMC4717871.
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Nutrition10 Common Nutrient Deficiencies