Mineral Requirements

Achieving a balanced and varied diet is usually adequate to provide us with sufficient nutrients to maintain general health and well being, and will contain enough essential nutrients i.e. vitamins,minerals,amino acids and essential fatty acids as well as carbohydrates and fats for energy. However, weight-loss pure vegetarian, macrobiotic, and several other diets can place some people at risk of deficiencies that vary with the type of diet.

Whilst there is standard guidance on the amounts of vitamins and minerals that should be consumed provided in the Recommended Daily Allowances or RDA, nutritional requirements will vary between individuals and depend on their time of life i.e. infancy, childhood, pregnancy, adulthood, old age - as well as the effects of genetics and lifestyle.

Certain groups of people have been found to be at especially high risk of dietary deficiencies.

Elderly - Studies have found that elderly people living in their own homes, often have dietary deficiencies of calcium, and zinc, and occasionally

Pre-menopausal women have been found often to consume low amounts of calcium and iron.

Mineral Deficiencies

Sodium

The Food Standards Agency hopes the 26m people who it says are consuming more salt than is healthy for them will heed its health warnings. High salt consumption can contribute to high blood pressure, which can lead to heart disease and stroke, it says. However, salt manufacturers say the government's £4m campaign is unfairly targeting one of life's essentials. The FSA said every day at least 26m people eat more than the recommended daily limit of 6g of salt. Men are eating almost double that, with a daily average of 11g of salt while women consume an average of 8.1g a day.

Approximately 75% of salt consumed is from processed foods, 10-15% is added by consumers and 10-15% is naturally present in food, the FSA said.

Calcium

Calcium is the main constituent of hydroxyapatite, the principal mineral in bones and teeth, and is also used by the body in blood clotting mechanisms and nerve fucntion. Calcium absorption and excretion are controlled by several hormones and vitamin D, and so a Vitamin D deficiency can lead to weakened bones (rickets) because of the lack of calcium absorption.

An adequate calcium intake is vital to health, particularly in times of growth, eg childhood, adolescence, pregnancy, and also during lactation. Dietary sources are from dairy products, fish, and dark green leafy vegetables, white and brown flour and bread.

In particular, good calcium nutrition throughout life is essential for achieving peak bone mass and preventing deficiency-related bone loss.Peak bone mass is reached at the age of about 30-35 years. After this age, some loss of calcium from bone is normal and bone mass slowly decreases. However, severe loss causes the bones to become weak, brittle and to break easily. This condition is known as osteoporosis. Calcium supplements are usually effective in increasing bone mass in children and slowing bone loss in adults, and have been shown to reduce the risk of bone fractures in some elderly adults, along with exercise.

Phosphorus

Phosphorus is a necessary nutrient, and is an essential component of all cells and is present in bones and teeth. Phosphorus is unlikely to be in short supply in UK diets as it is found in many foods. For this reason, many multivitamin-mineral supplements do not contain phosphorus. Phosphorus is present in all plant and animal cells, and 80% of the phosphorus in the body is present as calcium salts in the skeleton.

Magnesium

Magnesium is present in all tissues including bone, and it is believed that supplementation may help prevent bone loss. In the cells of the body magnesium is involved in energy transfer enzyme activity and muscle function. Magnesium is found in the diet in chlorophyll, the green pigment in plants. Dark green leafy vegetables contain plentiful amounts, but much of its bound and not readily available for absorption.

Deficiency of magnesium in the diet can lead to depression, irratibility, fits, tiredness and in extreme circumstances, heart attack. Dietary recommendations are different between the EU and US, but US based studies have found that dietary magnesium deficiency may occur in up to 25% of adult women in the U.S. and in even higher numbers of elderly people of both sexes.

Potassium

Potassium is found in body fluids and is essential for the proper functioning of cells, including nerves. It is present in almost all foods, especially fruit and vegetables, but processed foods contain less than raw foods. Potassium deficiency is not usually a problem in the UK, although some drugs can increase potassium losses. Where deficiency does occur it can cause weakness, mental confusion, and in extreme cases heart failure.

Iron

Iron is found in plant and animal sources. Iron from animal sources is better absorbed than iron from plant sources. Absorption of plant iron is affected by various factors in food, including tea and coffee, fibre, and calcium which can reduce absorption, although the presence of Vitamin C, which is also present in fruit and vegetables, will aid absorption.

Iron is required for the formation of haemoglobin in red blood cells which transport oxygen around the body. A lack of iron leads to low iron stores in the body and eventually to iron deficiency anaemia. Loss of blood due to injury or large menstrual losses increase iron requirements. Women and teenage girls in particular, need to ensure their diet supplies enough iron.

Iodine

iodine is used to make thyroid hormones. The thyroid hormones control many metabolic activities and if there is insufficient iodine in the diet, the result is lethargy and swelling of the thyroid gland in the neck to form a goitre. Infants born of severely iodine deficient mothers may be mentally retarded (cretinism). Nowadays this is rare in the UK.

The introduction of iodised salt and the presence of added iodine in many foods means that generally, deficiency in the western diet is rare. Most people have adequate iodine intake unless they avoid iodised salt, seafood and sea vegetables. People with thyroid diseases should check with their doctor before using iodine supplements.

Zinc

Zinc deficiency is not common in Western countries, except in people with low incomes. Zinc is present in many enzymes and is required for growth, tissue repair, immune function and for sexual maturation. In some countries the delay of puberty and small stature have been linked to zinc deficiency, though it is not certain that this is due to zinc alone. Zinc is present in many foods and is most readily absorbed from meat.

Prostatic secretions are known to have a high concentration of zinc, which suggests that zinc plays a role in normal prostate function. The EU Recommended Daily Allowance is set at 15 mg/day of Zinc, which is the amount required to avoid deficiency. There is no other definitive data on the amount required to support healthy prostate function specifically, or in those people with BPH.

Copper

Good sources of copper include green vegetables, fish and liver. Under normal circumstances, dietary deficiency is extremely rare.

Manganese

Manganese deficiency is rare, although it has been known in people whose diet consists primarily of processed foods which may have low manganese content.

Studies have not investigated the health effects of manganese supplementation. Manganese deficiency has been associated with osteoporosis in an unpublished study, and other studies using a combination of mineral supplements including manganese were shown to help prevent bone loss in postmenopausal women. Manganese is also believed to play a role in cartilage formation.

Iron supplementation can reduce manganese absorption and cause lower body levels of manganese.

Chromium

Chromium deficiency has been associated with blood sugar and cholesterol abnormalities. Also, chromium levels in the body decline as people get older, which is when these problems often appear. Therefore, while the effects of chromium supplements have not been studied in diabetes or heart disease, many healthcare practitioners recommend chromium supplements as a reasonable precaution.

Chromium nutrition has been difficult to study because of technical problems in analysing foods and human body fluids for chromium content. Partly for this reason, there is disagreement about the extent of potential chromium deficiency in Western societies.

Selenium

Dietary intake of selenium appears to be adequate in most people, and is present in cereals, meat, fish, offal, cheese and eggs.

Selenium is a component of some of the enzymes which protect the body against damage due to oxidation, and at very high levels can be toxic. Selenium deficiency has been linked with a form of heart disease (Keshan disease) in parts of China where soil levels of selenium are very low. It is possible that low levels of intake are associated with the increased risk of some cancers.

Molybdenum

Molybdenum is an essential trace element with low potential for toxicity. Since little is known about human needs and deficiencies are quite rare, estimated requirements are based on what people typically receive in their diets.

© LEV