Like most people, you probably take vitamin C to boost your immune system. But did you know that vitamin C has many other benefits – including decreasing fatigue?
Studies are showing that vitamin C has all sorts of benefits – in addition to decreasing fatigue, it can also positively influence heart rate and perceptions of exertion during moderate exercise. Better still, it looks as though vitamin C can also assist with weight loss in overweight and obese individuals.
What is vitamin C?
Vitamin C (also known as ascorbic acid) is an essential nutrient – our body requires it to properly function. Vitamin C is used to repair damaged tissue, make neurotransmitters and enzymes, as well as help your immune system function properly. (
In cell reactions, vitamin C donates its electrons. This is what gives it the label as an antioxidant. Our bodies can only store a small amount of vitamin C, so supplementing vitamin C regularly is important.
The World Health Organization (WHO) recommends a daily intake of 45mg, and a weekly intake of 300mg. Below, are the five best sources of vitamin C: ()
- Kale (120mg/100g)
- Kiwi (90mg/100g)
- Strawberry (60mg/100g)
- Oranges/Lemons (53mg/100g)
- Pineapple (50mg/100g)
Vitamin C is hard to obtain through meat products. Some organ meats, like chicken liver, contain adequate amounts however levels decrease substantially after the meat is cooked. Thus, vitamin C is best obtained through fruits and vegetables.
Unfortunately cooking and storing of fruits and vegetables quickly decreases the quantity of available vitamin C. To ensure you’re getting enough vitamin C in your diet, consume 1-2 servings of raw fruits and vegetables on a daily basis.
Vitamin C was the very first vitamin to be manufactured in a lab. (3) If you are unable to obtain enough vitamin C through your diet, a supplement of 500-1000mg per day is a good alternative.
Vitamin C and fatigue
In one study, overweight adults were put on a calorie restricted diet and given a moderate exercise plan to follow. Participants had to walk on a treadmill for 60 minutes at 50% of their maximum oxygen consumption. They were divided into two groups: one group received 500mg of vitamin C supplementation while the other group did not. The study lasted for a total of four weeks.
Through the study, participants were asked to rate their fatigue levels. Examiners also tracked oxygen consumption, heart rate, and perceived exertion. The results of the study were fascinating: ()
- Both groups lost 4kg.
- The heart rate of the group that supplemented vitamin C was significantly decreased.
- 11 bpm decrease in the group that supplemented vitamin C.
- 3 bpm decrease in the placebo group.
- General fatigue score was greatly reduced in the group following vitamin C supplementation.
- The group supplementing vitamin C perceived exercise to be less strenuous than the placebo group.
This study was done with a very small sample size of twenty participants so we can’t draw grandiose conclusions that vitamin C is a guaranteed way to decrease fatigue. However, the results look promising.
Additionally, vitamin C has an impeccable safety record. Vitamin C supplementation is a safe, cost-effective way to potentially increase your energy. I’d recommend it as a first-line therapy in the treatment of fatigue.
How vitamin C affects fatigue levels
Vitamin C is a required cofactor for the production of carnitine. Carnitine is a fatty acid transport molecule that facilitates the burning of fat during exercise. If you have low levels of vitamin C, you’re likely to have low levels of tissue carnitine. With low levels of carnitine, your body will struggle to burn fat during exercise.
Remember, fat can be a great source of energy. Those on a ketogenic or low carbohydrate diet will be primarily burning fat for fuel. Without adequate levels of vitamin C (and consequently, low levels of carnitine) fatigue will become more prevalent. Especially during exercise when your body is trying to use body fat for its energy source. (5)
If you find that you’re struggling to lose body fat with your exercise program, try taking an additional serving of fruits and vegetables each day. Or, opt for a vitamin C supplement of 500-1000mg.
Vitamin C and adrenal fatigue
In a previous post, I outline the best supplements for adrenal fatigue. Vitamin C is one of them. One of the highest concentrations of vitamin C just so happens to be located in your adrenal glands. (6) When your body is exposed to a stress (this could be blood sugar imbalancessleep irregularities</hidden sources of inflammation, or life-related stressors) cortisol is released to help your body best cope with the stress. Vitamin C is required by your adrenal glands to produce the cortisol hormone.
In fact, vitamin C is so important in cortisol production (and therefore stress management) that when ultramarathoners supplemented vitamin C following a race it helped to lower inflammation and improve the circulation of cortisol. (7<) If vitamin C helps reduce the effects of stress in such an intense situation, it is safe to assume that it will also be of benefit in your own life.
If you’ve been diagnosed with adrenal fatigue (also known as hypothalamic pituitary adrenal axis dysfunction or HPA-D) or you suspect that you have it, increasing your vitamin C intake should be one of your first steps. I always advocate starting with whole foods before reaching for supplements. If the whole foods are not improving your fatigue levels, then opt for a supplement. 500-1000mg per day is a perfect place to start.
Fortunately, vitamin C is water soluble. Therefore, if you take too much of it, your body will not accumulate the vitamin in toxic amounts. Instead, you’ll likely experience diarrhea, nausea, heartburn, and/or stomach cramps. 2000mg/day is thought to be the upper limit.
Ok, now you know how vitamin C can improve your fatigue and energy – click here to learn more about which foods increase your energy!
Also published on Medium.