How common are nutrient deficiencies?
It is often difficult to link one vitamin with a particular disease except in severe cases where a deficiency results in well-documented physical symptoms. For example, bleeding gums are a sign of scurvy which is caused by lack of vitamin C, and goiter is caused by an iodine deficiency.
Nutrient deficiencies occur for several reasons; including inadequate intake, inadequate absorption, inadequate utilization, increased requirement, increased excretion and increased breakdown. Anyone in whom these situations are found is at risk of deficiency. In developed countries, where the food supply is good, there are relatively few cases of severe deficiency. However, the statistics given above suggest that marginal deficiencies may be common.
Nutrient deficiencies can be classified into five stages:
A preliminary deficiency.
A biochemical deficiency where the nutrient concentration in the tissues becomes lower.
A physiological stage where the critical body processes, such as enzymes and hormones that depend on the nutrient are slowly lost. The first three stages are sub-clinical or marginal stages.
A clinical stage where the signs of the deficiency are obvious and can be detected by the eye.
An anatomical stage which can lead to death.
Marginal deficiency symptoms are nonspecific and can often go unnoticed or be attributed to other causes. When combined with other factors such as disease, prescription drugs, stress, smoking and pollution, they can increase susceptibility to illness or lead to clinical deficiencies. It is possible that marginal nutrient deficiencies play a role in many of the diseases of old age such as osteoporosis, arthritis, heart disease and high blood pressure. Ensuring optimal intakes of vitamins and minerals is therefore vital for present and future health.
What are the signs of marginal nutrient deficiencies?
There are many signs of marginal nutrient deficiencies and these can often be similar for different nutrients. In many cases, the only signs of a marginal deficiency will be vague symptoms such as fatigue, lethargy, difficulty concentrating or just feeling that things are not quite right. Diagnosing marginal deficiencies is difficult as many laboratory tests are expensive and time- consuming, if they are available at all. Marginal deficiencies of single nutrients are rare as it is likely that a person whose diet is deficient in one vitamin or mineral is deficient in others too. Some marginal deficiency symptoms include:
Bruising easily may be linked to vitamin C and K deficiency.
High cholesterol may be due to antioxidant vitamin and B complex deficiencies.
Reduced taste sensation may be due to zinc deficiency.
Fatigue may be due to iron, vitamin B12, folic acid or iodine deficiency.
High blood pressure may be due to potassium and calcium deficiencies.
Muscle cramps and pains may be due to calcium and magnesium deficiencies.
Osteoporosis may be linked to calcium deficiency.
There is increasing evidence to suggest that long-term marginal intake of certain nutrients can increase the risk of developing degenerative diseases such as cancer, diabetes and heart disease.