Vitamin C Supplements and Performance

Introduction

I love my oranges! Navels are the favourite but the Valencia’s do it for me too. Two-three a night after a meal. I know the Vitamin C in the oranges I eat are an essential component of a healthy diet. I know it also helps prevent and recover from colds and aids in the absorption of iron from meats. Increasing research evidence also suggests vitamin C acts as an antioxidant helping to reduce the effects of muscle damage after hard training, reduce immune system dysfunction after travel, stressful life events and hard training, and also help minimise fatigue from hard training. However, here is a review of the limited research done on the effects of vtamin supplementation on sports performance that suggest doses greater then1 gram per day of vitamin C may impair sport performance, possibly by reducing the rebuilding of the muscle aerobic power generators – the mitochondria.

The Research

The author is a sport scientist at the Olympic Training Center in the USA. She did a Google Scholar search using the keywords vitamin C, exercise, and athletes. and came up with an initial list of 42 articles published between 1985 and Jannuary, 2012. 12 of these were included in her review because they met the criteria of measuring athletes doing high intensity training and testing, they reported actual test data, and the athletes were supplemented with vitamin C using valid research methodologies. Here’s what the research showed.

The Results

The review found that:

  1. Supplementation with vitamin C in doses of greater than 1.0 grams per day may impair sport performance.
  2. Doses of approximately 0.2 grams per day of vitamin C consumed through five or more servings of fruit and vegetables (see Table below) may be sufficient to reduce oxidative stress and provide other health benefits without impairing training adaptations.
  3. Higher intakes between 0.2 and 1.0 grams per day might be recommended for short periods of time (1-2 weeks) during onset of illness, when stressed, or during periods of stress or intensified training such as at training camps.

The So What?

The recommended daily intake of vitamin C for ‘healthy’ adults is 60 mg per day. Sources of vitamin C can be found in the table below or by clicking here.

Food Source

Vitamin C (mg / 100 gm)

Strawberries

60

Oranges

50
Lemon

40

Cauliflower

40

Spinach

30

Carrots

10

Potato

20

Blackcurrants

200

Brussels sprouts

80
Capsicums (Green)

240

Oysters

30

Beef liver

30

This may not be enough for athletes like ourselves who train hard regularly. The above research review suggests dosages of around 0.2 grams per day are needed for athletes. So I’m sticking to my 2-3 oranges a night along with my daily feast of carrots and green veges. It also highlights one of the major tenures of my book The Masters Athlete that nutrition, use recovery strategies and ways of staying well, particularly for masters athletes who train and work hard, are critical to improve or maintain performance. Chapters 14, 15 and 16 of my book actually spell out the why’s and how’s of recovering faster, staying well and eating as an older athlete. Eat and recover well to stay well to perform well.

Braakhuis, A. (2012). Effect of vitamin C supplements on physical performance. Current Sports Medicine Reports. 11(4): 180-184.