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The recommended daily amount (RDA) of a nutrient is determined by how much the body needs to stay healthy. Nutrients can be obtained in a variety of ways—from eating a varied diet to taking vitamin supplements.
A nutritional deficiency occurs when the body doesn’t absorb the necessary amount of a nutrient. Deficiencies can lead to a variety of health problems, such as problems of digestion, skin problems, stunted or defective bone growth, and even dementia.
The most widespread nutritional deficiency worldwide is iron deficiency, which can result in anemia. Iron is found in foods such as red meat, dark, leafy greens, and egg yolks. It helps your body make red blood cells. When you’re iron-deficient, your body produces a reduced amount of red blood cells. The red blood cells it produces are smaller and paler than healthy blood cells.
According to the World Health Organization, over 30 percent of the world’s population suffers from this condition. It is prevalent in both developing and industrialized countries (WHO). In fact, iron deficiency anemia affects so many people that it is now widely recognized as a public health epidemic.
According to the WHO, a lack of vitamin A is the leading cause of preventable blindness in children. Pregnant women who are deficient in vitamin A have higher maternal mortality rates as well (WHO). Vitamin A is crucial for eye health and functioning, reproductive health in men and women, and also strengthening the immune system against infections. For newborn babies, the best source of vitamin A is breast milk. For everyone else, it is important to eat plenty of foods that are high in vitamin A, including green-yellow vegetables such as carrots, kale, broccoli, and sweet potatoes, or reddish-yellow fruits like apricots, papaya, and peaches.
Another common nutritional deficiency occurs with vitamin B1, also known as thiamine. Thiamine is essential for normal nerve function. Deficiency can lead to nerve and muscle damage and can affect the heart. A prolonged thiamine deficiency is also known as beriberi.
A deficiency of the vitamin B3, or niacin, is often referred to as pellagra. Niacin is found in most proteins. As a result, this condition is rare in meat-eating communities. Symptoms of pellagra include diarrhea, dementia, and skin problems. In extreme cases, it can cause sudden death.
Vitamin B9, often referred to as folate, helps the body create red blood cells and produce DNA, and also aids in brain development and nervous system functioning. Folate is especially important for fetal development, and plays a crucial role in the formation of a developing child’s brain and spinal cord. Folate deficiency can lead to severe birth defects, growth problems, or anemia. Folate is found in foods such as beans, citrus fruits, dark, leafy vegetables, and meats such as poultry, pork, and shellfish.
According to the National Institutes of Health, women who are pregnant or who may become pregnant are encouraged to take up to 400 micrograms of folate each day to prevent serious birth defects (NIH, 2011).
According to the Vitamin D Council, this type of deficiency is a growing global epidemic, affecting more than 50 percent of the population worldwide (VDC, 2012).
Vitamin D is essential for healthy bones and helps the body maintain the right levels of calcium in order to regulate the development of teeth and bones. A lack of this nutrient can lead to stunted or defective bone growth. Osteoporosis, caused by a lack of calcium and vitamin D, can lead to porous and fragile bones that break very easily. It can often be asymptomatic (without symptoms). The best sources of vitamin D are sun exposure and foods such as cod liver oil, salmon, or dairy products that have been fortified with vitamin D. According to the National Institutes of Health’s Office of Dietary Supplements, approximately 5-30 minutes of sun exposure twice a week can provide sufficient vitamin D (NIH, 2011).
Calcium aids in the development of strong bones and teeth, and also helps the heart, nerves, and muscles function properly. A calcium deficiency often shows no immediate symptoms, but can lead to serious health problems over time. Calcium deficiencies are related to low bone mass, weakening of bones due to osteoporosis, convulsions, abnormal heart rhythms, or even death.
The best sources of calcium are dairy products such as milk, yogurt, and cheese; vegetables like kale and broccoli, and calcium-fortified cereals and grains.
A poor diet that lacks essential nutrients generally causes nutritional deficiencies. The body stores nutrients. Therefore, a deficiency is usually detected after a prolonged lack of a nutrient.
A number of diseases and conditions—including colon cancer and gastrointestinal conditions—can lead to an iron deficiency. Pregnancy can also cause a deficiency if the body diverts iron to the fetus.
The symptoms of a nutritional deficiency depend on which nutrient the body lacks. However deficiencies can cause general symptoms. These include:
You may display all of these symptoms or only groups of them. Over time, most people adapt to the symptoms. This causes the condition to go undiagnosed. Schedule a check-up with your healthcare provider if you experience prolonged periods of fatigue, weakness, and poor concentration. These symptoms could indicate the beginning of a serious deficiency.
Your doctor will discuss your diet and eating habits with you if he or she suspects a nutritional deficiency. He or she will ask what symptoms you’re experiencing. Make sure to mention if you have suffered from any periods of constipation or diarrhea, or if blood has been present in your stool.
Your nutritional deficiency may also be diagnosed during routine blood tests, including a complete blood count (CBC). This is often how doctors identify anemia.
The treatment for a nutritional deficiency depends on the type and the severity of the deficiency. Your doctor will assess the severity of the deficiency and the likelihood of long-term problems caused by the lack of nutrients. He or she may order further testing to identify damage before deciding on a treatment plan. Symptoms usually fade when the correct diet is followed or supplemented—even with permanent conditions.
A doctor may advise you on how to change your eating habits in the case of a minor deficiency. For example, anemia sufferers should include more meat, eggs, poultry, vegetables, and cereals.
Your doctor may refer you to a dietician if your deficiency is more severe. He or she may recommend keeping a food diary for a number of weeks. When you meet with the dietician, you’ll go over the diary and identify changes you should make.
Typically, you will meet with the dietician regularly. Eventually, you may have a blood test to confirm that you are no longer nutrient deficient.
In some cases, a nutritional deficiency may require supplements or a multivitamin. It may also be necessary to take an additional supplement to help with absorption, such as taking calcium and vitamin D together.
The frequency and dosage of a supplement will depend on how severe the deficiency is, and will be decided by your doctor or a dietician.
In very severe cases, such as when a nutritional deficiency does not respond to oral medications, it may be necessary for the nutrient to be administered parenterally (through the veins or muscles). This can carry the risk of additional side effects, and usually administered in a hospital.
Parenteral iron, for example, can cause chills, backache, dizziness, fever, muscle pain, fainting, and even severe allergic reaction. Once the treatment has been administered, a repeat blood test will be done to confirm that it was successful. It may be necessary to attend the hospital for repeat appointments until the deficiency is resolved.
Most problems caused by nutritional deficiencies will stop once the deficiency has been resolved. However, in some cases, there may be lasting damage. This typically only occurs when the deficiency has been severe and has lasted a long time.
For example, a prolonged vitamin B1 deficiency can be associated with:
Written by: Kati Blake
Published on Jul 26, 2012
Updated on Feb 15, 2013
Medically reviewed by George Krucik, MD
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