di Emine Meral Inelmen
Cattedra di Geriatria-Direttore: Prof. Enzo Manzato
Dipartimento di Medicina- DIMED

Universita' degli Studi di Padova
email: eminemeral.inelmen@unipd.it

Introduction

It now 100 years since the term "vitamin" was coined and it have been learned a lot about its role in human health, yet a considerable proportion of the elderly population still does not meet recommended vitamin intakes (1). In fact, the study of Toffanello et al, 2011 (2) confirmed that an inadequate vitamin intake (hypovitaminosis) is a common finding in elderly people. The low vitamin status in the elderly may not come as a surprise considering their dietary habits. In fact, changes in dietary habits which may occur in advanced age (3), might influence the variety of an elderly's diet, leading to a deficient intake of specific vitamins. Various studies have pointed to the existence of vitamin deficiencies in the elderly as a result of an inadequate dietary intake; in fact, it is well known that vitamin intake is positively associated with energy intake, since it is hard to obtain adequate supplies of vitamins when a person's energy intake is lower than 1550 Kcalories (4). A poor intake of such essential vitamins as vitamin B1 (thiamine), vitamin A, C and D has been confirmed in large proportion of older people as a consequence of a reduced food intake due to dietary restrictions (2).

The recommended vitamin levels in elderly : an open-ended question

At this point it can be claimed that proper vitamin nutrition is essential for all people but especially for elderly persons, because they are at higher risk for deficiency than younger adults. Factors such as decreased income, physical activity and energy needs, lack of social contact, dementia and other psychological factors typically lead to decreased food intake and consequently affect vitamin status (5).

However, the question of whether vitamin deficiencies might occur or increase in elderly people remains open (2).

People age differently, and the course of the aging process beyond 65 years old can be classified as successful, typical or accelerated, and there is no agreement in the current literature as to whether a decline in food intake unavoidably occurs in all elderly, even in those aging successfully (2).

Thus, there are several difficulties in selecting a sample of elderly people for a food intake study. Some authors suggest the selection of apparently healthy elderly. Even if it possible to obtain an almost homogeneous group, this is not a "real" sample of an elderly population, which is, on the contrary, characterized by a high heterogeneity of subjects: self-sufficient, not self-sufficient and institutionalized. In Italy, the recommended nutrient levels (LARN) are valid for a population up to 60 years old, while all the elderly are placed in an unique "geriatric" group of age, over 60 (6). Hence, it should be necessary to know exactly the vitamin intake levels requested by the elderly, in each decade of advanced age (6), since over the last decade, a number of studies have explored the effects of vitamin intakes beyond the daily recommendations on a variety of mostly chronic diseases (1). Given the magnitude of the problem, Troesch and Eggersdorfer, 2012 (1) had called to action for all stakeholders involved-academia, health professionals, industry, funding agencies, and policy makers-to find ways to close the gap between recommended and actual vitamin intakes in the elderly.

Recommended vitamin intakes are not met in elderly

In U.S. over 80% of persons age 71 years old had intakes of "empty calories" (solid fats, added sugars, and alcoholic beverages) that exceeded the discretionary calorie allowances (7). This excess appears to be displacing nutrient-rich food groups and may be contributing to the obesity epidemic by providing many individuals with unnecessary "empty calories" (7) and hypovitaminosis. Nearly the entire U.S. population consumes a diet poor in vitamins, with fewer vegetables and whole grains than recommended, and a large majority under-consume fruits, milk, oils relative to recommendations (7). These findings add another piece to the rather disturbing picture that is emerging of a nation's diet (7).

In the Italian elderly people also, there is significant increase in the consumption of "empty calorie" foods (sugars, sweets), especially in women (2) which might be responsible for hypovitaminosis (vitamin A and vitamin B2) .

Vitamin reference intakes and aging

To the light of that already said, the effect of aging on vitamin requirements is not easy to quantify. There are changes reported in the literature that give the impression that the demand for some essential vitamins, such as vitamin A and the vitamin B complex, may increase in later life, possibly due to chronic conditions and morbidity. The epidemiological findings suggest that intakes of particular vitamins are related to the incidence of chronic diseases common in elderly.

The Food and Nutrition Board, the Institute of Medicine, and the National Academy of Science and Health of Canada have recently developed a standard set of nutrient recommendations, known as dietary reference intakes (DRIs), which has added, with regard to vitamin intakes, the groups for ages 51-70 years and for 70 years and older (5).These recommendations are listed in Table 1.

Vitamins and chronic diseases

Vitamins that act as antioxidants appear to have a role in preventing coronary artery disease and cancer (8). Current work is focusing on the actions of vitamins as related to immune function, the formation of cataracts, and the development of osteoporosis, all associated with aging. A low intake in B vitamins is thought to impair cognitive function and the capacity to perform the activities of daily living in elderly.

The following paragraphs show the most common vitamins at which the elderly may be at risk of hypovitaminosis, and their relation with chronic diseases.

Vitamin D

Vitamin D (calciferol) is essential for mineral homeostasis and for normal mineralization of the skeleton. Vitamin D is a generic name for allsteroids that show the biological activity of vitamin D3 (cholecalciferol). It increases the absorption of calcium and phosphates, and influences kidney re-absorption of amino acids. Vitamin D deficiency is particularly important in the elderly population because it is common and has a direct relationship with increased morbidity (5).The deficiency of vitamin D is linked to osteomalacia, osteoporosis, and increased vertebral and non-vertebral fractures. Vitamin D is obtained from two sources, diet and skin formation: the elderly receive less exposure to sunlight and synthesis in the skin is reduced by about 50% (9). In fact, an inverse relation exists between the concentrations of pro-vitamin D3 in the epidermis with age (10). Over two thirds of the elderly have vitamin D intakes that are below two thirds of the RDA (11). Supplementation has been shown to increase bone mineral density and decrease fracture risk (12). In fact, in residential aged care, routine vitamin D supplementation is highly effective in preventing falls and fractures (13). On the other hand, excessive intakes cause increased calcium absorption and increased calcium mobilization from bone, resulting in hypercalcaemia and soft tissue calcification (14).

Vitamin E

Alpha-tocopherol is the biologically active form of vitamin E and is probably the major lipid-soluble antioxidant. Vitamin E absorption seems to be not altered with aging ; deficiency of vitamin E has not been reported for healthy elderly people (14). Low levels of alpha-tocopherol may be associated with an increased risk of cancer mortality; because of these effects of vitamin E deficiency, the use of supplemental vitamin E has been investigated to prevent cancer (14). Clear benefit has only been associated with reducing the risk of prostate cancer (15).

Vitamin C

Also known as ascorbic acid, vitamin C is obtainable only through dietary sources. It is claimed that five servings of fruit and vegetables per day can supply the RDA (5). Like vitamin A and E, vitamin C is an antioxidant and reduces harmful free radicals (5). The conversion of iron from ferric to ferrous form requires vitamin C; without this conversion, methaemoglobin could not be converted to haemoglobin, and iron could not be absorbed in the duodenum (5). Scurvy is the clinical syndrome of vitamin C deficiency.

Vitamin A

Vitamin A is the generic name for compounds with the qualitative biological activity of retinol, i.e. retinoids, beta-carotene and pro-vitamin A carotenoids. Low serum retinol levels indicate vitamin A deficiency. The effects of vitamin A deficiency are night blindness (hemeralopy), dry-eyes syndrome, keratomalacia, Bitot's spots on the conjunctiva, dry skin and follicular hyperkeratosis. Toxicity has been associated with abuse of vitamin A supplements and with diets extremely high in vitamin A content (16).

Vitamin K

The forms of vitamin K include phylloquinone, which is found in plants, and the menaquinones, which are synthesized by gut bacteria. Vitamin K is necessary for the synthesis of clotting factors 2, 7,9 and 10 and for the synthesis of protein C and protein S (17). Causes of vitamin K deficiency include any source of fat malabsorption and drugs that interfere with vitamin K metabolism, such as anticonvulsants, warfarin and certain antibiotics (17). The major clinical feature of vitamin K deficiency is bleeding.

Vitamin B1 (or thiamine)

The active form of thiamine, thiamine pyrophosphate, is a coenzyme involved in energy metabolism reactions; the requirement for thiamine is therefore related to energy expenditure. Patients at risk for vitamin B1 deficiency include alcoholics, those on chronic peritoneal dialysis, those re-fed after starvation, and thiamine-depleted persons who are given glucose. Patients at high risk, such as alcoholics, may benefit from supplementation (5). Excessive amounts of ingested thiamine are rapidly cleared by the kidneys. No evidence exists of thiamine toxicity by oral administration.

Vitamin B2

Vitamin B2 is also known as riboflavin. It is an essential component of flavin mononucleotide and flavin adenine dinucleotide, both of which are involved in ATP synthesis (5). Deficiency may result from insufficient dietary intake or from medical conditions such as chronic diarrhea, alcoholism, or liver disease (5).

Vitamin B3

Vitamin B3 is niacin, also known as nicotinic acid. The metabolically active forms of niacin are the pyridine nucleotides, nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) (18). Free forms of the vitamin are white stable crystalline solids. Only small amounts of the free forms of niacin occur in nature. Most of the niacin in food is present as a component of NAD or NADP. Pellagra is the clinical manifestation of niacin deficiency.

Vitamin B6

Vitamin B6 occurs in three forms, pyridoxine, pyridoxal and pyridoxamine; all of them are phosphorylated and pyroxal-5'-phospate is the active coenzyme form of many enzymes involved in protein and amino acid metabolism. Deficiency is associated with seborrhoeic dermatitis, epileptiform convulsions and anaemia (14) .The elderly tend to be at greater risk of vitamin B6 deficiency, even if it is widely available in most foods.

Vitamin B12

Vitamin B12 includes the cobalamins, which can be converted to methyl- or 5'-deoxyadenosyl cobalamin, which qualitatively exhibit the biological activity of cyanocobalamin. Deficiencies due to inadequate intake are rare. However, negative vitamin B12 balance is often found in the elderly, especially in those with atrophic gastritis, Helicobacter pylori infection and use of proton pump inhibitors or other agents that interfere with gastric acidity (5). A significant increase in malabsorption of vitamin B12 seems to occur with age (5). The main symptoms of deficiency are anaemia and/or neuropsychological disorders.

Folate

Folate is the generic name for folic acid-related compounds. They are mainly involved in thymidine synthesis. There seem to be no age-related changes in folate metabolism. Folate is ubiquitous in nature and is present in nearly all natural foods. Deficiencies are characterized by anaemia (megaloblastic), depression and dermatological lesions. Alcohol and drug intake increase the risk of deficiency. Folate deficiency can occur within a few days of insufficient intake. This deficiency is a particular risk in the elderly who have recently been institutionalized (5). Deficiency in these persons is presumably caused by decreased food choices and possibly by depression.

Conclusion

Vitamin requirements and metabolism should be studied more closely in the elderly. Nutritional guidelines for elderly people should urge them to consume a variety of foods from all the food groups and to choose- instead of "empty calorie" foods- more nutrient-dense foods in order to ensure that their vitamin intakes reach the recommended levels. Specific vitamin supplementation may therefore be necessary in elderly people, even if they are apparently healthy, to ensure adequate vitamin intake.

References

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Campigotto F, Sergi G, Coin A, Miotto F, Enzi G, Manzato E. Ten-Year Trends in Vitamin Intake in Free-Living Healthy Elderly People: the Risk of Subclinical Malnutrition J Nutr Health Aging 2011; 15: 99-103.
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the capacity of human skin to produce vitamin D3. J
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(13) Waldron N, Hill AM, Barker A. Falls prevention in older adults - assessment and management. Aust Fam Physician 2012;41:930-35.
(14) Inelmen EM, Sergi G. Biochemical Parameters of Nutrition In: Cachexia and Wasting: A Modern Approach edited by Giovanni Mantovani, Stefan D. Anker, and Akio Inui, et al, New York, NY, Springer, 2006. Chapter 3.1 pp,1-14.
(15) Stephenson J. Vitamin E and prostate cancer. JAMA 1998; 279: 1153.
(16) Guigoz Y Recommended dietary allowances
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(17) Goljan EF. Disorders of nutrition. In: Pathology.
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(18) Swendseid ME, Jacob RA Niacin. In: Shils ME,
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Table 1. Recommended Vitamin Intake in Elderly People