Age has an important impact on body composition. The decreases of lean body mass and total body water accompanied by an increase of body fat are the most relevant changes leading to a reduction of the basal metabolic rate. Due to this and the fact that elderly people are generally less physically active, energy needs are lower. However, the requirements for most micronutrients are not reduced. Indeed, impaired absorption of some vitamins and minerals like cobalamin and calcium can cause deficiencies. An adequate calcium supply is particularly important as with ongoing age, bone mass decreases as well, making elderly prone to osteoporosis. The reduced ability to synthesize vitamin D and the lower sunlight exposure of many elderly further aggravate this issue. There is evidence to consider the supply of some important dietary antioxidants as critical in some elderly, namely vitamin C and β-carotene as well as zinc. In light of age-related decreases in the activities of antioxidant enzymes, a sufficient supply of dietary antioxidants is important, especially as oxidative damage is thought to contribute to the deteriorating processes associated with aging and promote cardiovascular disease, cognitive disorders, cancer and diabetes mellitus that occur more frequently in older people. The first three are also associated with an insufficiency of folate, another critical nutrient in the elderly. Therefore, dietary guidelines should strive to optimize the immune function and reduce disease risk of the elderly.

Evidence exists that well-planned vegetarian diets provide numerous health benefits and are appropriate for all stages of the life cycle. It is also known that animal foods provide micronutrients that are nonexistent or available only in limited amounts in plant foods. Restriction or exclusion of all animal foods may therefore result in low intake of certain micronutrients such as vitamin B-12, thereby affecting vitamin B-12 status and elevating plasma homocysteine concentrations. Overall, the studies we reviewed showed reduced mean vitamin B-12 status and elevated mean homocysteine concentrations in vegetarians, particularly among vegans. Low vitamin B-12 intake may lead to decreased bioavailability and functional deficiency of cobalamin. Although early noticeable symptoms of vitamin B-12 deficiency are nonspecific (unusual fatigue, digestion problems, frequent upper respiratory infections), the best-known clinical manifestations of cobalamin malabsorption are hematologic (pernicious anemia) and neurologic symptoms. Hyperhomocysteinemia is associated with an increased risk of atherosclerosis and cardiovascular disease. Given these health concerns, vegetarians, particularly vegans, must be advised to carefully plan their diets, to monitor their plasma vitamin B-12 on a regular basis to facilitate early detection of low cobalamin status, and to use vitamin B-12–fortified foods or take vitamin B-12 supplements if necessary.

Adequate protein intake is critical for health and development. Generally, protein of animal origin is of higher quality for humans owing to its amino acid pattern and good digestibility. When administered in mixtures it can enhance the quality of plant proteins, but its availability is often low in low-income communities, especially in young children, the elderly, and pregnant and lactating women, who have increased requirements and in whom high-quality protein also stimulates (bone) growth and maintenance. Although high protein intake was associated with increased type 2 diabetes mellitus risk, milk and seafood are good sources of branched chain amino acids and taurine, which act beneficially on glucose metabolism and blood pressure. However, high consumption of protein-rich animal food is also associated with adverse health effects and higher risk for noncommunicable diseases, partly related to other components of these foods, like saturated fatty acids and potential carcinogens in processed meat but also the atherogenic methionine metabolite homocysteine. In moderation, however, animal proteins are especially important for health maintenance in vulnerable persons.

Background/Aim: The objective of this review was to collect data on the dietary intake of total fat and saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), especially linoleic (LA), α-linolenic (ALA), eicosapentaenoic and docosahexaenoic fatty acids, in adults from various countries and to compare them with current recommendations for fat intake. Methods: Weighted mean intake data were collected from national dietary surveys, large cross-sectional studies and/or studies with focus on health and nutrition. Thereof, only studies with diet recalls, weighing records or food frequency questionnaires were considered. Results: Data from 28 countries were included, representing Africa (3), America (4), Asia (5), Australia/New Zealand (2) and Europe (14). Total fat intake ranged from 11.1 (China, Guangxi Bai Ku Yao and Han populations) to 50.7 (rural dwellers in Nigeria) percentages of total energy (%E). SFA intake varied from 3.1 (China, Guangxi Bai Ku Yao and Han populations) to 25.4%E (rural dwellers in Nigeria). Mean MUFA and PUFA intake ranged from 3.5 (China, Guangxi Bai Ku Yao and Han populations) to 22.3 (Greece), and 3.3 (India) to 11.3%E (Taiwan), respectively. The mean intake of LA and ALA was between 2.7 (India) and 7.2 (Austria), and 0.4 (France) and 1.0%E (Finland). Conclusion: With regard to recommendations for fat intake, no general advice for improvements can be given worldwide. Due to different dietary patterns, only regionally specific recommendations can be made about what would be necessary to modify and improve fat quantity and quality of the diet.