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FOR IMMEDIATE RELEASE
Orthomolecular Medicine News Service, December 8, 2009
 

VITAMIN C AND ACIDITY
What Form is Best?

(OMNS, December 8, 2009) Vitamin C is commonly taken in large quantities to improve health and prevent asthma, allergies, viral infection, and heart disease [1,2]. It is non-toxic and non-immunogenic, and does not irritate the stomach as drugs like aspirin can. Yet vitamin C (L-ascorbic acid) is acidic. So, a common question is, what are the effects from taking large quantities?

Ascorbic acid is a weak acid (pKa= 4.2) [3], only slightly stronger than vinegar. When dissolved in water, vitamin C is sour but less so than citric acid found in lemons and limes. Can large quantities of a weak acid such as ascorbate cause problems in the body? The answer is, sometimes, in some situations. However, with some simple precautions they can be avoided.

Acid in the Mouth
First of all, any acid can etch the surfaces of your teeth. This is the reason the dentist cleans your teeth and warns about plaque, for acid generated by bacteria in the mouth can etch your teeth to cause cavities. Cola soft drinks contain phosphoric acid, actually used by dentists to etch teeth before tooth sealants are applied. Like soft drinks, ascorbic acid will not cause etching of teeth if only briefly present. Often, vitamin C tablets are coated with a tableting ingredient such as magnesium stearate which prevents the ascorbate from dissolving immediately. Swallowing a vitamin C tablet without chewing it prevents its acid from harming tooth enamel.

Chewable Vitamin C Tablets
Chewables are popular because they taste sweet and so are good for encouraging children to take their vitamin C [4]. However, some chewable vitamin C tablets can contain sugar and ascorbic acid which, when chewed, is likely to stick in the crevices of your teeth. So, after chewing a vitamin C tablet, a good bit of advice is to rinse with water or brush your teeth. But the best way is to specifically select non-acidic vitamin C chewables, readily available in stores. Read the label to verify that the chewable is made entirely with non-acidic vitamin C.

Stomach Acidity
People with sensitive stomachs may report discomfort when large doses of vitamin C are taken at levels to prevent an acute viral infection (1,000-3,000 milligrams or more every 20 minutes) [1, 5]. In this case the ascorbic acid in the stomach can build up enough acidity to cause heartburn or a similar reaction. On the other hand, many people report no problems with acidity even when taking even 20,000 mg in an hour. The acid normally present in the stomach, hydrochloric acid (HCl), is very strong: dozens of times more acidic than vitamin C. When one has swallowed a huge amount of ascorbate, the digestive tract is sucking it up into the bloodstream as fast as it can, but it may still take a while to do so. Some people report that they seem to sense ascorbic acid tablets "sitting" at the bottom of the stomach as they take time to dissolve. It is fairly easy to fix the problem by using buffered ascorbate, or taking ascorbic acid with food or liquids in a meal or snack. When the amount of vitamin C ingested is more than the gut can absorb, the ascorbate attracts water into the intestines creating a laxative effect. This saturation intake is called bowel tolerance. One should reduce the amount (by 20-50%) when this occurs [1].

Acid Balance in the Body
Does taking large quantities of an acid, even a weak acid like ascorbate, tip the body's acid balance (pH) causing health problems? No, because the body actively and constantly controls the pH of the bloodstream. The kidneys regulate the acid in the body over a long time period, hours to days, by selectively excreting either acid or basic components in urine. Over a shorter time period, minutes to hours, if the blood is too acid, the autonomic nervous system increases the rate of breathing, thereby removing more carbon dioxide from the blood, reducing its acidity. Some foods can indirectly cause acidity. For example, when more protein is eaten than necessary for maintenance and growth, it is metabolized into acid, which must be removed by the kidneys, generally as uric acid. In this case, calcium and/or magnesium are excreted along with the acid in the urine which can deplete our supplies of calcium and magnesium [6]. However, because ascorbic acid is a weak acid, we can tolerate a lot before it will much affect the body's acidity. Although there have been allegations about vitamin C supposedly causing kidney stones, there is no evidence for this, and its acidity and diuretic tendency actually tends to reduce kidney stones in most people who are prone to them [1,7]. Ascorbic acid dissolves calcium phosphate stones and dissolves struvite stones. Additionally, while vitamin C does increase oxalate excretion, vitamin C simultaneously inhibits the union of calcium and oxalate. [1,2].

Hi Alobar,
   This is XXXXXXXX, wanted to thank you for that post on smoking. that lj put it in the forefront of my mind that i cannot start smoking again like i used to.  i had been without a cigarette for over ten years and started up less than two weeks ago.

Will find better ways to deal with life.  Your aptly put homage of "fucktard" did it for me because it is the truth.

sincerely
XXXX