This article is about the most common deficiencies and how to avoid them. But first let me share my own experience with nutritional deficiencies with you.
Initially when I got interested in a healthier lifestyle I was only concerned with the amount of calories I was consuming in my diet. Once I had a good understanding of calories my focus shifted to the macronutrient composition of my diet, that is the composition of carbohydrates, protein and fat.
Only much later did I realise that I was not really addressing the importance of micronutrients (vitamins and minerals). Looking back I think I paid the price for it. At times I felt tired, lacked focus and concentration and experienced bad memory. I have since started taking a supplement that contains both vitamins and minerals and all of these problems have disappeared.
The moment I noticed it the most was while I was studying Chinese characters one day. It used to take me a long time to remember them but all of a sudden it became much much easier. The difference was so significant that studying the characters actually became much more fun.
That said, I still think that supplementation should be kept at a minimum. Therefore I'm taking a supplement that does not contain more than 100% of the RDA for all of the vitamins and minerals.
In 2012, the Centers for Disease Control and Prevention published the second nutrition report showing measures of 58 indicators of diet and nutrition in the US. The report found that less than 10% of the U.S. population had nutrition deficiencies for the selected indicators.
However, it was also found that some population groups show a much higher rate of deficiencies (in some cases as high as 30%). One example is vitamin D deficiency. While a very low percentage of non-Hispanic white people (3%) were found to have a vitamin D deficiency, rates among non-Hispanic black (31%) and Mexican-American (12%) are much higher.
So even though only 10% of Americans seem to face nutritional deficiencies, you might have a higher risk of facing one if you are in a particular population group. Let's look at the most common deficiencies vitamin B6, vitamin D and iron.
According to the CDC report about 10% of the US population is vitamin B6 deficient. Vitamin B6 is important for healthy brain function, the formation of red blood cells, the break down of protein and creation of antibodies. A deficiency is associated with muscle weakness, irritability, depression and poor memory and concentration.
It is found in a wide variety of foods such as fish, beef liver, potatoes, starchy vegetables and fruit. Most American get their vitamin B6 from fortified cereals, beef, poultry, starchy vegetables and non-citrus fruit.
The recommended dietary allowance (RDA) for men and women is 1.3 mg per day.
About 8% of the US population is vitamin D deficient. However as stated above, some population groups have a much higher risk of being deficient. 31% of non-Hispanic black and 12% of Mexican-American people are Vitamin D deficient.
The problem with vitamin D is that it's naturally present in only very few foods. The body can produce vitamin D internally when exposed to sunlight. However, especially in winter we are often not getting enough sun exposure to produce adequate levels of vitamin D.
Many foods in the US are fortified with vitamin D including breakfast cereals, milk, some brands of orange juice, yoghurt and margarine.
Overall people with limited sun exposure and people with dark skin are at risk of not getting enough vitamin D.
The RDA for vitamin D is 600 international units (IU) for both men and women.
The WHO states that iron is the number one nutritional deficiency in the world. As many as 80% of the world's population may be iron deficient. About 10% of the US population is iron deficient. Signs of iron deficiency include feeling tired and weak, decreased work performance, slow cognition during childhood and decreased immune function.
Iron is naturally found in animal foods such as red meat, fish and poultry and plant foods such as lentils, beans and spinach. Many cereal brands are iron fortified. Just one cup of these cereals often provides the daily recommended amount of iron already.
While it is important to get enough iron in your diet, it's even more important to not get excessive amounts of iron since it can result in toxicity and even death. Men need about 8 mg per day and women need about 18 mg per day (women lose more iron due their menstrual cycle). The tolerable upper intake levels for adults are 45 mg per day.