Even when your food intake is good, inefficient digestion can limit your body's uptake of vitamins. Some common causes of inefficient digestion are not chewing well enough and eating too fast. Both of these result in larger than normal food particle size, too large to allow complete action of digestive enzymes. Many people with dentures are unable to chew as efficiently as those with a full set of original teeth.
Hot Coffee, Tea and Spices
Habitual drinking of liquids that are too hot, or consuming an excess of irritants such as coffee, tea or pickles and spices can cause inflammation of the digestive linings, resulting in a drop of secretion of digestive fluids and poorer extraction of vitamins and minerals from food.
Drinking too much alcohol is known to damage the liver and pancreas which are vital to digestion and metabolism. It can also damage the lining of the intestinal tract and adversely affect the absorption of nutrients, leading to sub-clinical malnutrition. Regular heavy use of alcohol increases the body's need for the B-group vitamins. Particularly thiamine, nicotinic acid, pyridoxine, folic acid and vitamins B12, A and C as well as the minerals zinc, magnesium and calcium. Alcohol affects availability, absorption and metabolism of nutrients.
Smoking too much tobacco is also an irritant to the digestive tract and increases the metabolic requirements of vitamin C, all else being equal, by at least thirty per cent more than the typical requirements of a non-smoker. Vitamin C which is normally present in such foods as paw paws, oranges and capsicums, oxidises rapidly once these fruits are cut, juiced, cooked or stored in direct light or near heat. Vitamin C is important to the immune function and is a protector vitamin.
Overuse of laxatives can result in poor absorption of vitamins and minerals from food, by hastening the internal transit time. Paraffin and other mineral oils, increases the loss of fat soluble vitamins a, E and K. Other laxatives used to excess can cause large losses of minerals, such as potassium, sodium and magnesium.
Bizarre diets that miss out on whole groups of foods can be seriously lacking in vitamins. Even the popular low fat diets, if taken to an extreme, can be deficient in vitamins A, D and E. Vegetarian diets, which exclude meat and other animal sources, must be very skillfully planned to avoid vitamin B12 deficiency, which may lead to anaemia.
Lengthy cooking or reheating of meat and vegetables can oxidise and destroy heat susceptible vitamins such as the B-group, C and E. Boiling vegetables leaches the water-soluble vitamins B-group and C. As well as many minerals. Light steaming is preferable. Some vitamins, such as vitamin B6, can be destroyed by irradiation from microwaves.
Freezing food containing vitamin E can significantly reduce its levels once defrosted. Foods containing vitamin E exposed to heat and air can turn rancid. Many common sources of vitamin E, such as bread and oils are nowadays highly processed, so that the vitamin E level is significantly reduced or missing totally. This increasing the storage life of the bread but can lower nutrient levels. Vitamin E is an antioxidant which defensively inhibits oxidative damage to all tissues. Other vitamin losses from food preserving can include vitamins B1 and C.
A diet overly dependent on highly refined carbohydrates, such as sugar, white flour and white rice, places greater demand on additional sources of B-group vitamins to process these carbohydrates. An unbalanced diet contributes to such conditions as irritability, lethargy and sleep disorders.
Some antibiotics although valuable in fighting infection, also kill off friendly bacteria in the gut, which would normally be producing B-group vitamins to be absorbed through the intestinal walls. Such deficiencies can result in a variety of nervous conditions, therefore it may be advisable to supplement with B-group vitamins when on a lengthy course of broad spectrum antibiotics.
The omission of whole food groups from the diet, as is the case of individual allergies to gluten or lactose, can mean the loss of significant dietary sources of nutrients such as thiamine, riboflavine or calcium.
Crop Nutrient Losses
Some agricultural soils are deficient in trace elements. Decades of Intensive agriculture and overwork may deplete soils, unless all the soil nutrients, including trace elements, are regularly replaced.
Accidents and Illness
Burns lead to a loss of protein and essential trace nutrients such as vitamins and minerals. Surgery increases the need for zinc, vitamin E and C and other nutrients involved in the cellular repair mechanism. The repair of broken bones will be retarded by an inadequate supply of calcium and vitamin C and conversely enhanced by optimum dietary supply. The challenge of infection places high demand on the nutritional resources of zinc, magnesium and vitamins B5, B6 and C.
Chemical, physical and emotional stresses can increase the body's requirements for vitamins B2, B5, B6 and C. Air pollution increases the requirements for vitamin E.
Research has demonstrated that up to 60% of women suffering from the symptoms of premenstrual tension, such as headaches, irritability, bloatedness, breast tenderness, lethargy and depression can benefit from supplements such as vitamin B6 and evening primrose oil, a source of essential fatty acids.
Rapid growth spurts such as in the teenage years, particularly in girls, place high demands on nutritional resources to underwrite the accelerated physical, biochemical and emotional development in this age group.
Pregnancy creates higher than average demands for nutrients, to ensure healthy growth of the baby and comfortable confinement of the mother. Nutrients which typically increase during pregnancy are the B-group, especially B1,B2,B3,B6, folic acid and B12,A,D,E and the minerals calcium, iron, zinc, magnesium and phosphorus. Note: professional assessment of nutrient requirements during pregnancy should be sought.
Oral contraceptives can decrease absorption of folic acid and increase requirements for vitamins B6 and C, zinc and riboflavine.
Some people eat very sparingly, even without weight reduction goals.
The aged have been shown to have a low intake of vitamins and minerals, particularly iron, calcium and zinc. Folic acid deficiency is often found in conjunction with vitamin C deficiency. Fibre intake is often low. Riboflavine and pyridoxine deficiencies have also been observed. Possible causes include reduced sense of taste and smell, reduced secretion of digestive enzymes, chronic disease and some drug therapies.
Lack of Sunlight
Invalids, shiftworkers and people whose exposure to sunlight is minimal can suffer from insufficient amounts of vitamin D, which is required for calcium metabolism, without which rickets and osteoporosis has been observed.
Wide fluctuations in individual nutrient requirements from the official average vitamin and mineral intakes are common, particularly for those in high physical demand vocations, such as athletics and manual labour, taking into account body weight and physical type.
Low Body Reserves
Although the body is able to store reserves of certain vitamins such as A and E, data has shown that up to 30% of the Indian population e.g. had low "at risk" levels of vitamin A.
Athletes consume large amounts of food and are subject to considerable stress. Test on athletes have shown a wide range of risk deficiencies including B-group vitamins, vitamin C and zinc and iron.
Air pollution exposes the human body to substances capable of endangering health and depletion of vitamin reserves. These substances include carbon monoxide, aldehydes, hydrocarbons, nitrogen oxides, sulphur dioxides and positive ions (also found in air conditioned rooms). Vitamin A helps to protect the body from air pollutions toxic effects. Vitamin E protects against the toxic effects and oxidation reactions caused of many of the chemicals found in Air Pollution and Vitamin C may help facilitate the detoxification of the constituents of Air Pollution.
Pesticides pose a risk in any area where the tap water is from an underground source and in areas where agriculture is a major part of the economy. Pesticides are also prevalent in the home where sprays are used and as a residue on fruit and vegetables not classified as organic or biodynamic. Some pesticides mimic estrogen in the body and others tend to tend to accumulate in the fatty tissues of the body. Exposure to pesticides and toxins gives rise to many health problems and places pressure on the human body, for example load on the liver, nervous system, hormonal system and respiratory systems. Vitamins and minerals (eg zinc, selenium, magnesium, calcium) possess actions which help the body to deal with toxic chemicals and heavy metals.