Vitamin Status and Requirements of the Older Adult - Chapter 4

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