Table of Contents
Table of Contents
The World Health Organization estimates that over 2 billion people suffer from dietary deficiencies of vitamins and minerals. And in the US, data from the National Health and Nutrition Examination Survey (NHANES) and the United States Department of Agriculture's Food Consumption and Nutrient Intakes for Americans indicate that nutrient deficiencies affect a substantial portion of the US population, perhaps as high as 80% for some vitamins and minerals.
Addressing these nutritional gaps is critical in supporting metabolic health, immune function, and general physiology in these individuals.
Common micronutrient deficiencies include:
The most common vitamin and mineral deficiencies worldwide are vitamins A and D3 and iron. These nutrients are especially important to those populations where overall nutritional adequacy is not met.
An individual's vitamin and mineral intake can range from severe deficiency to toxicity. Somewhere in between is the ideal intake level. Two related terms are widely used to set a standard for the desired intake: Recommended Dietary Allowance (RDA) and Recommended Dietary Intake (RDI).
One of the biggest criticisms of the RDA is that it is not based on defining the optimal level of nutrient intake, but rather on the level that will not result in any signs of deficiency and on an estimate of the physiological need for the nutrient in "healthy" people.
Between the level of deficiency and an adequate or optimal level lies an area referred to as subclinical, marginal, or nutrient insufficiency. These terms signify a level of nutrient intake above causing classic deficiency signs and symptoms, but is less than optimal because it is associated with some evidence of physiological inadequacy. In many instances, the only clues of a subclinical nutrient deficiency may be fatigue, lethargy, difficulty concentrating, or a lack of well-being. Worse, chronic, long-term subclinical deficiency may wear down our health over time.
Vitamins and minerals are essential nutrients, meaning the body cannot function correctly without them. One of the main functions of vitamins and minerals is that they are found in the active part of the enzymes, and coenzymes work together to build or break down molecules.
Most enzymes contain a protein and a cofactor, typically an essential mineral or vitamin. If an enzyme lacks an essential mineral or vitamin, it cannot function properly. The enzyme can perform its vital function by providing the necessary minerals and vitamins through diet or a nutritional formula. For example, zinc is required for the enzyme that activates vitamin A in the visual process. A diet with sufficient vitamin A is irrelevant because vitamin A cannot convert to the active form without zinc in the enzyme.
Many enzymes also require additional support to perform their function. The support is in the form of a coenzyme, a molecule that functions along with the enzyme. Coenzymes are often composed of a vitamin or mineral. Without the coenzyme, the enzyme is powerless.
In the body, micronutrients (vitamins and minerals) function interactively. A deficiency of any single vitamin or mineral disrupts this complex system and must be avoided to achieve and maintain health.
Vitamin A was the first fat-soluble vitamin discovered. Vitamin A is critical to the health and function of the immune system and plays a vital role in maintaining optimal eye health and vision.
It is an unfortunate reality in this era of modern living that inadequate Vitamin A intake affects over 500 million people, creating significant vision and immune health challenges in many parts of the world. While severe inadequacy is rare in the United States and other developed countries, suboptimal intake remains a major factor in underdeveloped nations. To support global wellness and vision health, international organizations often administer routine Vitamin A supplementation (e.g., 4,000 mcg of retinol) to at-risk populations.
Suboptimal vitamin A levels can leave individuals more susceptible to poor immune resilience. Adequate intake is also essential for maintaining the healthy mucous membranes that line the respiratory, gastrointestinal, and genitourinary tracts. Furthermore, a lack of adequate Vitamin A can significantly impact the eyes. Insufficient levels can affect everyday visual acuity, particularly night vision, and compromise the normal moisture, comfort, and structural integrity of the eye's outer layers.
Vitamin A is available in the diet in two forms. Retinol is preformed vitamin A, and beta-carotene is converted by the body into retinol. Unfortunately, during periods of suboptimal overall nutrition or when zinc intake is inadequate, the conversion of beta-carotene to vitamin A is impaired. In addition, due to genetics, as many as 25% of people poorly convert beta-carotene into vitamin A.
Dietary sources of retinol include eggs, butter, fortified milk and dairy products, beef liver, chicken liver, and cod liver oil. Nutritional sources of beta-carotene include green leafy vegetables and orange-colored vegetables and fruit (such as carrots, sweet potatoes, winter squash, cantaloupe, and mangos). In general, the greater the intensity of the color of the fruit or vegetable, the higher the beta-carotene level. For example, kale is considerably higher in beta-carotene than lettuce.
Medical professionals typically evaluate Vitamin A status by measuring blood levels of retinol. While severe shortages are rare in the US, approximately 46% of adults have an inadequate intake of vitamin A.
Vitamin A activity was initially measured in international units, with an IU being defined as 0.3 mcg of crystalline retinol or 0.6 mcg of beta-carotene. In 1967, the WHO recommended that vitamin A activity be referred to in terms of retinol active equivalents (RAE) rather than in I.U., with 1 mcg of retinol being equivalent to 1 RAE. In 1980, this recommendation was adopted in the US, and the RDA for vitamin A is now stated in RAE, although it is still common to see vitamin A activity listed in IU. The RDA for men and women is 900 and 700 RAE, respectively. The Tolerable Upper Intake Level (UL) for adults is set at 3,000 RAE of preformed vitamin A to avoid toxicity. There is no set UL for beta-carotene because the body will not form retinol from beta-carotene if levels are sufficient.
Warning: Dosages of retinol greater than 3,000 mcg (3,000 RAE or 10,000 IU) are not recommended for women at risk of pregnancy. High dosages of preformed retinol are contraindicated during pregnancy due to potential developmental risks and should be avoided by any woman who might be pregnant.
There has been a big buzz about the importance of vitamin D3 because of its critical role in immune health. But vitamin D3 is vital to many cellular functions throughout the body. Vitamin D3 acts more like a "prohormone" than a traditional vitamin. We produce vitamin D3 in our bodies through a chemical reaction in our skin in response to sunlight. This vitamin D3 is converted by the liver to 25(OH)D3 and then by the kidneys to its most active hormonal form, 1,25-dihydroxyvitamin D3 or calcitriol, which plays a key role in calcium metabolism as well as in the expression of the genetic code. Human DNA contains more than 2,700 binding sites for the most active forms of vitamin D3.
Considerable evidence indicates that about 50% of the world's population may have suboptimal levels of vitamin D3.
In the US, about 70% of the population has inadequate vitamin D3 intake (i.e., blood levels below 30 ng/ml), and about half fall into the lowest brackets of vitamin D status (25(OH)D3 with levels below 25 ng/ml), including a large percentage of older adults in care facilities and 76% of expectant mothers.
Suboptimal vitamin D3 status is conventionally understood as having a 25(OH)D3 blood level of less than 25 ng/ml or even lower. The target blood level to ensure adequate D3 status is generally considered to be 40 ng/ml. But many health and wellness experts consider a blood level of 50–80 ng/ml to be the optimal range.
Vitamin D is known as the "sunshine vitamin" because the skin can form vitamin D3 when exposed to the sun. Foods and supplements can also supply preformed D3. The best dietary sources are fatty fish, beef liver, egg yolks, and D3-fortified dairy products. The D2 form of the vitamin is found in mushrooms, some fortified foods, and dietary supplements. However, the D2 form is not as efficient at raising blood levels as D3. The preferred supplement form is generally vitamin D3.
Given the widespread occurrence of suboptimal 25(OH)D3 blood levels, many wellness experts recommend daily supportive vitamin D3 supplementation to help maintain optimal health across all age groups, generally following these guidelines:
The importance of iron as the central portion of the hemoglobin molecule of red blood cells (RBC) is well-known. Iron is critical in the transport of oxygen from the lungs to the body's tissues and the transport of carbon dioxide from the tissues to the lungs. Iron plays a crucial role in enzymes involved in DNA and cellular energy production.
Suboptimal iron intake is generally regarded as one of the most common nutritional gaps in the world, including the United States. It is estimated that roughly one-fifth of the world's population has inadequate iron levels. The groups with the highest risk for suboptimal iron status are infants under two years of age, teenage girls, expectant mothers, and the elderly. Studies have found evidence of inadequate iron intake in as many as 30–50% of people in these groups, and even higher rates among those following a vegan lifestyle.
Inadequate iron levels may be due to an increased iron requirement, decreased dietary intake, diminished iron absorption or utilization, everyday blood loss (such as through menstruation), or a combination of factors. Increased requirements for iron occur during the rapid growth phases of infancy and adolescence, as well as during pregnancy and lactation. Currently, expectant mothers are routinely advised by their healthcare providers to take iron supplements, as the dramatically increased need for iron during pregnancy cannot usually be met through diet alone.
Severe, prolonged iron shortages can significantly impact red blood cell health. However, it is important to note that iron-dependent enzymes involved in energy production and metabolism are often the first to be affected by suboptimal iron levels.
Even marginal iron insufficiency can significantly impact the function of many tissues in the body. In particular, it can lead to everyday fatigue and affect normal immune system resilience and brain function. Suboptimal iron levels can reduce exercise stamina, physical work capacity, and the immune system's natural defenses. It is also associated with decreased attentiveness, a narrower attention span, and occasional low mood. Fortunately, supporting healthy iron intake can help maintain normal cognitive focus, mental stamina, and physical energy.
Adequate iron intake in children is particularly crucial, as prolonged shortages can impact normal physical and cognitive development. Suboptimal iron status can leave children falling short of their full potential regarding everyday attention span and learning capacity, whether they live in a developed or underdeveloped country.
Medical professionals typically evaluate iron status using a blood test known as serum ferritin. For optimal wellness, the level is generally considered ideal at 60 ng/ml or higher for iron sufficiency.
The best dietary sources of iron are red meat, especially liver. Good non-meat sources of iron include fish, beans, molasses, dried fruits, whole-grain and enriched breads, and green leafy vegetables. However, iron is better absorbed from meat because it is bound to hemoglobin. Non-heme iron absorption is significantly less compared to heme-iron (approximately a 5% absorption rate for non-heme vs. 30% for heme-iron). The RDA for iron is 18 mg for women and 10 mg for men.
The most popular iron supplements are ferrous sulfate and ferrous fumarate. However, highly regarded forms include ferrous bisglycinate and ferric pyrophosphate. Both are generally well-tolerated by the gastrointestinal system and offer higher relative bioavailability, especially if taken on an empty stomach.
Many wellness experts recommend taking a daily supplement providing 30 mg of iron to help maintain a positive iron status for individuals following a plant-based or vegan diet.
For those looking to support their iron levels, a common supportive intake is 30 mg of iron twice daily between meals. If this recommendation results in occasional abdominal discomfort, the intake can be divided and taken with meals three to four times daily.
A health-promoting diet is critical for establishing a solid nutritional foundation to build upon with a strategic supplement program. No amount of dietary supplements can take the place of this foundation. However, we can use supplements to provide nutritional "insurance" in meeting dietary needs for optimal health.
References:
DISCLAIMER: These statements have not been approved by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent disease.
