Vitamin C, or ascorbic acid, is an essential nutrient for humans because all higher primates lost the ability to make it internally over the course of evolution. As such, while your dog doesn’t need to eat foods containing vitamin C or take supplemental tablets, you must. The amount of vitamin C needed each day is not well understood and has been debated for decades. The current recommended daily allowance, or RDA, is fairly easily met by most Americans, although some health experts believe that much more is needed each day for optimum health. If much higher amounts are needed, then vitamin C tablets are an affordable and convenient way of meeting those needs.
Vitamin C Recommendations
The RDA of vitamin C for adults ranges from 75 to 125 milligrams and depends on gender, pregnancy, lactation and cigarette smoking. These amounts are based on the prevention of obvious deficiency issues, collectively known as scurvy at its most advanced stage, and not based on promoting health. In contrast, many health experts, including the two-time Nobel Laureate Dr. Linus Pauling, recommend daily amounts of between 500 and 3,000 milligrams of vitamin C. Most medical doctors consider mega-dosing vitamins and minerals as worthless or even dangerous, but mounting scientific evidence suggests that the current RDA levels of vitamin C are too low. For example, higher primates housed in zoos are typically given more than 20 times the human RDAs of vitamin C just to maintain basic health.
Vitamin C is needed to make and maintain collagen, which is an elastic substance in all connective tissues, blood vessels, bones and muscles. Without appropriate vitamin C levels, your skin loses its elasticity, your ligaments, tendons and cartilage break down, and your cardiovascular system deteriorates. Vitamin C is also a strong antioxidant, which reduces oxidation damage caused by free radicals and is helpful for preventing cataracts and healing stomach ulcers. It’s also an effective antimicrobial, helping to deter the proliferation of pathogenic microorganisms. Furthermore, vitamin C stimulates the production and activity of specialized immunity cells and increases the absorption of dietary iron. Mega-dosing with vitamin C tablets is sometimes attempted in order to cure the common cold or prevent cancer, but not enough scientific evidence currently exists to support these uses.
Tablets vs. Natural Sources
If people need only about 100 milligrams of vitamin C daily, then a moderately healthy diet including fresh fruits and vegetables easily meets the requirements and vitamin C tablets are unnecessary for most Americans. However, if higher amounts are discovered as being necessary, say for example 500 milligrams daily, then at least 80 percent of Americans are deficient. Consuming 500 milligrams or more of vitamin C each day via fruits and vegetables is not practical or economically feasible for many Americans, so vitamin C tablets can be regarded as a convenient solution and readily available. More research is needed to determine the individual vitamin C needs for people.
Potential Side Effects
Your body has a limited capacity to process and absorb vitamin C taken orally via tablets. The capacity is different for everyone and can be slowly improved upon over time, but most people are likely to experience some side effects if they take more than 1,000 milligrams all at once. Side effects are relatively minor and essentially include stomach upset and diarrhea. Taking non-acidic, buffered vitamin C tablets is a good idea if you are considering taking more than the RDA levels.
- PDR for Nutritional Supplements; Sheldon Hendler and David Rorvik
- Textbook of Nutritional Medicine; Melvyn Werbach and Jeffery Moss
- Nutritional Sciences for Human Health; Stanislas Berger et al.
- Public Health Nutrition: From Principles to Practice; Mark Lawrence and Tony Worsley
Sirah Dubois is currently a PhD student in food science after having completed her master's degree in nutrition at the University of Alberta. She has worked in private practice as a dietitian in Edmonton, Canada and her nutrition-related articles have appeared in The Edmonton Journal newspaper.