Can we prevent or reduce symptoms of colds through nutrition?

Introduction

runny noseOn average, adults have 2-4 colds per year with kids having 6-8 bouts of the runny nose, sore eyes and sore throats a runny noseyear. Athletes of any age who train hard are increasingly susceptible to these upper respiratory infections, especially during the colder months. Apart from a visit to the family doctor for medications, we have been told that remedies such as honey and lemon drinks, echinacea, oranges or even a shot of rum or scotch may be the cure we need. This paper reviews the research evidence for nutritional remedies that may help prevent or treat the symptoms of the common cold.

The Research

The key to maintaining a healthy immune system is to eat a well-balanced and varied diet with plenty of fruit and vegetables. However, in winter, we tend to eat less fruit and vegetables – the opposite of what we should be doing. If we can’t get it fresh, then we should get frozen foods. This paper highlighted specific nutrients associated with enhancing the immune system. The table below shows those nutrients, their recommended daily allowances for adults, the upper limits recommended for intake before health is negatively affected, and common sources.

Nutrient

RDA

UTL

Sources

Selenium

55 μg

400 μg

Brazil nuts, canned tuna, beef, turkey

Zinc

11 mg (men) 8 mg (women)

40 mg

Oysters, beef, crab, pork, chicken

Copper

900 μg

10000 μg

Oysters, shellfish, nuts, green leafy veg

Iron

8 mg (men) 18 mg (women)

45 mg

Liver, oysters, beef, chicken, oats, soy

Vitamin A

3000 IU (men) 2310 IU (women)

10000 IU

Liver, carrots, spinach, apricots

Vitamin C

90 mg (men) 75 mg (women)

2000 mg

Red and green peppers, oranges

Vitamin E

15 mg

1000 mg

Wheat germ oil, almonds, peanuts

Vitamin B6

1.7 mg (men) 1.5 mg (women)

100 mg

Fortified cereals, potatoes, bananas

Folate

400 μg

1000 μg

Fortified cereals, liver, spinach

RDA = Recommended Daily Allowance; UTL = Upper Tolerable Limit; Source in bold – major source

A really cool and interactive site for seeing what your recommended intakes of these and ALL other nutrients is at: http://fnic.nal.usda.gov/interactiveDRI/ It also takes into account activity levels. It’s well worth the visit!

This paper highlighted that the following prevent colds:

  1. Vitamin C when taken at 200 mg/day, cuts the risk of colds by half, especially for athletes in cold environments.
  2. Moderate and regular exercise cuts the risk threefold; intense regular exercise increases risk.
  3. Vitamin E, Zinc and Garlic have no definitive research support for preventing colds.

This paper highlighted that the following reduce cold symptoms:

  1. Echinacea appears to reduce cold symptoms
  2. Zinc supplements and Vitamin C taken in doses greater than 200 mg/day, have no effect on reducing cold symptoms.

Gardener, L. (2009). Eat yourself cold free. Complete Nutrition. 4(6): 22-24.