Chapter 4Vitamin Status and Requirements of
the Older Adult
Introduction
• Interest in vitamin nutrition– Role in prevention and modulation of chronic
disease– Lifelong nutrition plays role in healthy aging
• Goals of nutrition therapy– Disease management– Health protection
Introduction
• Recommendations based on age– Age 51 to 70– Age 70 and older
Vitamin A
• Vitamin Forms and Precursors– Preformed Vitamin A
• Retinols– Provitamin A forms
• Carotenoids
Vitamin A
• Function– Maintains vision– Systemic functions– Affects gene expression– Required for bone health– Role in immunity– Antioxidant properties
Vitamin A
• Absorption– Retinols
• 70% to 90% absorption – Beta-carotene
• 20% to 50% absorption– Carotenoid lycopene
Vitamin A• Metabolism
– Found in three antioxidant levels• Protection against oxidative reactions• Scavenging free radicals• Repair of damaged molecules
– Major dietary carotenoids• Beta-carotene• Lutein and Zeaxanthin• Lycopene• Beta-cryptoxanthin
Vitamin A• Food Sources
– Foods of animal origin– Plants
Vitamin A
• Recommendations– Measured in Retinol Activity Equivalents (RAEs)
• Deficiencies– Age-related oxidative stress– Suboptimal intakes– Blood levels
Vitamin A
• Toxicity– Persons at risk– Increase the risk of osteoporosis and hip fractures– Symptoms of toxicity
Vitamin D• Forms
– Food sources– Sunlight
• Functions and Metabolism– Bone health and osteoporosis– Muscle and falls– Cancer– Cardiovascular disease– Diabetes mellitus
Vitamin D
• Absorption– Rate ~ 50%
• Recommendations– Based on plasma 25(OH)D and PTH levels
• Food Sources– Milk, fatty fish, fish oil, egg yolks, fortified foods
Vitamin D
• Deficiency– The lowest threshold value that prevents elevated
PTH level, bone turnover, and bone mineral loss
• Toxicity– Main adverse effects
• Hypocalcaemia• Enhanced bone resorption
Vitamin E
• Forms and Other Names– Natural occurring forms
• Tocopherols• Tocotrienols
– Esterified vitamin E• Food supplements• Cosmetic products
Vitamin E
• Absorption– Overall 20% to 50% absorption– Inversely related to intake– After absorption
• Secreted within chylomicrons• Transported through lymph system• Hydrolyzed and released to peripheral tissues
or transported to the liver
Vitamin E
• Metabolism– Oxidative Theory
• Scavenge free radicals– Injury Response Theory
• Inhibits or interferes with enzymatic activity
• Recommendations– Based on the alpha-tocopherol form
Vitamin E
• Food Sources– Only plant sources
• Deficiencies– Rare
• Genetic abnormalities• Fat malabsorption syndromes• Protein energy malnutrition
• Toxicity– Hemorrhagic toxicity
Vitamin K
• Forms– Phylloquinones– Menaquinones– Menadione
• Functions– Blood clotting– Bone formation
Vitamin K
• Absorption– Varies between 40% and 80%
• Metabolism– Bone metabolism– Possible protective role against osteoporosis
• Recommendations– 1,000 mcg recommended for optimal osteocalcin
levels
Vitamin K
• Food Sources– Green leafy vegetables, plant oils, and margarine
• Deficiency– Caution if using Coumadin (blood thinner) med
• Toxicities– Currently no UL
Summary Table of Fat Soluble Vitamins
The B-Complex Vitamins• Forms
– Vitamin B12• Corrinoids
– Vitamin B6• Pyridoxine, pyridoxal, and pyridoxamine
– Folate• Includes numerous forms
–Polyglutamate derivatives–Pteroylmonoglutamic acid
The B-Complex Vitamins
• Functions– Coenzymes
• Blood formation• Neurologic function• Involved in amino acid metabolism
• Absorption– Vitamin B12
• Influenced by normal aging changes of the gut and common disorders of older adults
The B-Complex Vitamins
Insel P, Turner RE, Ross D. Nutrition. 3rd ed. Sudbury, MA: Jones & Bartlett; 2007, p. 44. Reproduced with permission.
The B-complex Vitamins
• Absorption– Vitamin B6
• Not affected by age – Folate
• May or may not be affected by aging changes
The B-Complex Vitamins
• Metabolism– Function as co-enzymes of one-carbon units and
homocysteine• Elevated homocysteine risk factor for vascular
diseases–Atherosclerosis–Cognitive disorders–Diabetes mellitus– Inflammatory bowel disease–Role in other diseases
The B-Complex Vitamins
• Homocysteine metabolism–Methionine synthase pathway–Cystathionine pathway
– Involved in Kreb Cycle
The B-Complex Vitamins
The B-Complex Vitamins
• Homocysteine metabolism–Methionine synthase pathway–Cystathionine pathway
– Involved in Kreb Cycle
• Recommendations– B12– B6– Folate
The B-Complex Vitamins
• Food Sources– Vit B12
• Mainly animal sources and fortified foods– Vit B6
• Variety of foods– Folate
• Liver, leafy greens, fortified grains, citrus fruits
The B-Complex Vitamins
• Deficiency– Folate
• Fortification of grains – mandated–May mask Vitamin B12 deficiency
– Vitamin B12• Mainly caused by malabsorption
– Vitamin B6• Higher requirements in older adults
The B-Complex Vitamins
• Toxicity– Folate
• Associated with faster rate of cognitive decline of older adults
• Large amounts may mask neurologic damage of Vitamin B12 deficiency
Vitamin C
• Water-soluble• Variety of functions
– Antioxidant– Role in connective tissue, hormone, and
neurotransmitter synthesis
• Reduced absorption in older adults• Caution with high supplement doses• High requirement for smokers
Other B Vitamins
• Thiamin, niacin, riboflavin, biotin, and pantothenic acid– Release of energy from carbohydrates, proteins,
and fats• Adequately consumed among older adults• Deficiencies
– Poor dietary intake– Chronic medication use– Other lifestyle factors
Conclusion
• More research needed to understand how physiologic changes of aging relate to nutrition needs