Nutrition for Strength
The aging process, at least in inactive people, is accompanied by many physiological changes that affect nutritional needs. These are summarised in Table 1 below.
Table 1: Major age-related changes that may influence nutrient requirements of masters athletes.
| Age-related change | Nutritional implication |
|---|---|
| Decreased muscle mass | Decreased energy requirements |
| Decreased aerobic capacity | Decreased energy requirements |
| Decreased muscle glycogen (CHO) stores | Decreased energy requirements |
| Decreased bone density | Increased need for calcium and vitamin D |
| Decreased immune function | Increased need for vitamins B6, E and zinc |
| Decreased gastric acid | Increased need for vitamin B12, folic acid, calcium, iron and zinc |
| Decreased skin capacity for vitamin D synthesis | Increased need for vitamin D |
| Decreased calcium bioavailability | Increased need for calcium and vitamin D |
| Decreased liver uptake of retinol | Decreased need for vitamin A |
| Decreased efficiency in metabolic use of pyridoxal (one form of vitamin B6) | Increased need for vitamin B6 |
| Increased oxidative stress status | Increased need for vitamins A, C and E |
| Increased levels of homocysteine (an amino acid related to heart disease) | Increased need for folate and vitamins B6 and B12 |
| Decreased thirst perception | Increased fluid needs |
| Decreased kidney function | Increased fluid needs |
This table suggest that older people in general have increased needs for calcium, vitamins, and the minerals calcium, iron and zinc. However, when we talk about masters athletes who exhibit the changes outlined above, we must also consider the effects that exercise has on any individual young or old (see Table 2 below).
Table 2: The effects of aging and exercise on factors that affect nutrition.
| Factor | Aging Effect | Exercise Effect |
|---|---|---|
| Resting metabolic rate | ↓ | ↑ |
| Total energy expenditure | ↓ | ↑ |
| Thermic effect of food | ↓ | ↑ |
| Total body water | ↓ | ↑ |
| Total bone and muscle mass | ↓ | ↑ |
| Protein synthesis and turnover rate | ↓ | ↑ |
| Gut transit time of food | ↓ | ↑ |
| Appetite and energy intake | ↓ | ↑ |
| Glycogen storage capacity and uptake | ↓ | ↑ |
| Fat breakdown chemical activity | ↓ | ↑ |
| Cholesterol | ||
| Total | ↑ | ↓ |
| LDL Cholesterol | ↑ | ↓ |
| HDL Cholesterol | ↓ | ↑ |
| Growth hormone | ↓ | ↑ |