Updated: Nov 27, 2020
Vitamin C believe it or not is more than the popular vitamin in oranges, lemons and limes. Vitamin C is essential for human life. The vitamin also known as ascorbic acid, or "anti-scurvy", is a water-soluble vitamin (meaning we eliminate excess vitamin C in our urine) that plays crucial roles in the body as cofactor. Without vitamin C many enzymes in our body that make collagen, neurotransmitters, carnitine, neuropeptides and regulate gene expression would not function. Without it we would have many more problems than just getting sick more often. In fact vitamin C was discovered because of its ability to cure scurvy and saved lives because of it (1).
In developed countries scurvy is rare but there are still cases in those with very poor diets. Scurvy is a disorder caused by lack of vitamin C. Symptoms include anemia, bleeding gums, tooth loss, joint pain, fatigue and was fatal prior to discovering the treatment of vitamin C. Scurvy is treated by supplying foods and supplements high in vitamin C, and in the late 1700s the British navy found that eating oranges or lemons would cure the disease and prevent the symptoms in their sailors as they were out to sea (2).
Most animals like cats, dogs, mice, and rats make their own vitamin C, but we lack the enzyme gulonolactone oxidase and we must get it from out diet (3). In our Westernized world we also live a lifestyle that brandishes stress like a badge of honor, bragging about our long hours of work and busy lives. The problem with this is that stress whether physical, mental or perceived depletes vitamin C. In addition to stress we need higher vitamin C levels during specific circumstances and seasons of life (4):
As we age
Lack of acid production in the stomach
Consuming foods and drug products with binders (aluminum-containing phosphate binders)
Genetic mutations - may affect our ability to transport and store the nutrient in some tissues like our muscles and kidneys
Nutrient competition - vitamin C taken with iron and lutein will actually help it's absorption however too high of a single dose taken with vitamin B12 will decrease it's absorption.
Vitamin C deficiency resulting in Scurvy is extremely rare but given the conditions above occurring in tandem it is possible even in the US for some to experience poor wound healing and bruising easily, due to the weakening of blood vessels, which all contain collagen. Our body's ability to make collagen requires vitamin C. The really good news is that deficiency can be prevented by as little as 10 mg of vitamin C daily. And for most of us a 500 mg single dose is enough to saturate our blood levels and allow vitamin C to begin to accumulate in our muscles, bones, kidneys, brain, eyes, adrenal and pituitary glands and white blood cells. On a quick side note, vitamin C actually helps our body make more white blood cells - pretty neat ;) (4).
Fatigue may be more difficult to directly connect to a lack of vitamin C but can occur from low levels of carnitine. Vitamin C helps make carnitine in our body (via trimethyllysine hydroxylase). This molecule acts as a shuttle that brings fat into our mitochondria, where it is converted into energy by a process called beta-oxidation. Basically this means that vitamin C allows us to burn fat as fuel in our cells (5). Vitamin C also plays a key role in our body's ability to make adrenaline (using this term for both epinephrine and norepinephrine), a neurotransmitter/hormone, involved in our stress response and fight or flight response when we need to run for our lives, or fight for our lives. When adrenaline is released quickly in from our adrenal glands and the nerves in our muscles we that we get a burst of strength, quick movement and our heart muscle also starts pounding quickly in our chest (4).
Vitamin C helps make adrenaline in our adrenal glands, sympathetic nerves and our brain, where we see the most accumulation. In our brain and nerves Vitamin C uses its antioxidant function to make an enzyme in our neurons (tyrosine hydroxylase) more active and also signals to our neurons to start making more of the enzyme. Finally vitamin C uses it's antioxidant function to activate another enzyme that recycles dopamine and turns it into adrenaline (via dopamine β-hydroxylase). In our adrenal glands vitamin C is concentrated the most compared to other tissues in the body, and is actually released in response to both cortisol and norepinephrine. This suggests that vitamin C plays a key role in reducing stress hormones and neurotransmitters (6).
Interestingly in animals that can make their own vitamin C they have much lower circulating cortisol (another stress hormone) than primates and humans who are required to consume vitamin C. Scientists found that in animals who could naturally produce vitamin C on their own, production increased significantly during physically or psychologically stressful tests. Also in animals that could make their own vitamin C scientists ran an experiment where they blocked the animal's ability to make vitamin C naturally and found the cortisol levels to skyrocket, which also confirms vitamin C's ability to reduce stress hormones. There have been studies that show supplementation of vitamin C in humans and animals are associated with a decreased cortisol response after a psychological or physical stressor (7).
In a study published in the International Journal of Sports Medicine scientists wanted to see how extreme endurance athletes (ultramarathoners) would respond to a 500 mg dose or 1,500 mg dose of vitamin C, or placebo for 7 days before their race and 2 days after. Of course running an ultramarathon is a huge stressor on the body and produces massive amounts of oxidation and inflammation, as well as causes the production and release stress hormones as well. Researchers measured blood levels of cortisol, adrenaline and markers of inflammation before and 24 and 48 hours after the race. What they found was that cortisol was significantly lower in the 1,500 mg group compared to the 500 mg and placebo group. They also found the inflammatory and adrenaline levels to be significantly lower in the 1,500 mg group as well (8).
It's well known that obesity causes inflammation and a variety of other cardiometabolic issues in the body, such as high blood pressure. While this isn't exactly a stress response, obesity itself is a stressor of many systems in the body and excess fat tissue is known to produce inflammatory cytokines, which is also a burden on the body. In a recent study published in 2015, researchers looked at obese patients with high blood pressure and randomly picked individuals to either receive two does of 500 mg (1g/daily) of vitamin C, or no supplements at all for 8 weeks. After 2 months hs-CRP and IL-6, two inflammatory markers, were significantly reduced in the vitamin C group. What was also very interesting were the cardiometabolic benefits they found as well. Fasting blood glucose and triglycerides were also significantly lower in the vitamin C group compared to the controls. Total cholesterol was not lowered in the vitamin C group. The authors of the study went on to discuss the antioxidant capacity of vitamin C and how it acts as an anti-inflammatory within the body. And although blood pressure wasn't a measure this study looked at other studies have also shown fairly low doses of vitamin C can also benefit hypertension as well (9).
A review study from Johns Hopkins University School of Medicine, analyzed 29 randomized, controlled clinical trials and found that 500 mg /day dose of vitamin C was found to lowered blood pressure consistently. The reason for this is that vitamin C may act as a diuretic, causing the kidneys to remove more sodium and water from the body, which helps to relax the blood vessel walls, thereby lowering blood pressure (10).
Overall diet and other nutrients also plays a role on the level of cortisol our body produces. Cortisol isn't inherently bad, and is required to help us fight stress, by ensuring a stable level of glucose, stimulating tissue regeneration and inhibiting the inflammation processes. But factors like stressful work, intense study at school, intense exercise, mood disorders, poor relationships and personal problems can lead to long-term sustained, excessive amounts of this hormone. Excessive cortisol affects metabolic disorders such as insulin resistance, increased blood pressure, our ability to regenerate bone and synthesize collagen and retain calcium. Successful management of stress and resilience has to start with a diet high in fruits and vegetables which have the most naturally occurring vitamin C. Overall carbohydrate intake (and quality of carbs), B vitamins, magnesium, lithium, taurine, vitamin D, boron, omega-3's (DHA and EPA), vitamin E, a number of phytonutirents and caffeine intake have all shown to influence circulating levels of cortisol and our body's ability to produce the hormone (11).
If you're looking for some practical ways to reduce stress and anxiety look no further! I have a free class available. Grab some coffee and a notepad and create your anti-stress plan today! Class Link