Understanding acidifiers

Common additives that increase the acidity (lower the pH) of foods and beverages. Acidifiers provide tartness and enhance flavors of processed foods. The increased acidity inhibits the growth of microorganisms; thus acidifiers act as preservatives. Certain acidifiers can also retard spoilage by acting as antioxidants, preventing chemical changes due to oxygen. This group of additives includes ADIPIC ACID (adipate), TARTARIC ACID (tartrate), benzoic acid (benzoate), and CITRIC ACID (citrate).

Understanding acid-forming foods

Foods that create acidic residues after they have been broken down by the body. Protein-rich food, such as EGGS, MEAT, and poultry, produce acidic residues when oxidized for energy. The combustion of sulfur-containing amino acids tends to acidify the body (acidic residue). In contrast, fruits and vegetables make the body more alkaline or basic. They contain magnesium, calcium, and potassium salts of organic acids, which yield an alkaline residue when oxidized. Fruits are accordingly classified as alkali-forming foods, even though juices and fruit taste acidic (sour). Excretion of organic acids (potential renal acid load) can be calculated for various foods based on their content of sodium, potassium, calcium, magnesium, chloride, phosphorus, and sulfur. Choosing more alkaline foods may ameliorate osteoporosis, autoimmune conditions such as rheumatoid arthritis, and chronic inflammation.

Acid and human health

A large family of compounds that taste sour and can neutralize bases to create salts. Strong acids like hydrochloric acid (STOMACH ACID) and sulfuric acid (battery acid) give up all of their protons in water and lower the pH, the effective hydrogen ion concentration. A pH of 7.0 is neutral, that is, neither acidic nor basic, while pH values less than 7.0 are considered acidic. Exposure to strong acids tends to damage cells and tissues. The stomach is the only organ normally exposed to strong acids, but it is protected from injury by a heavy mucous layer.
In contrast to strong acids, organic acids are classified as weak acids because they donate only a portion of their hydrogen ions, lower the pH to a lesser degree, and are less dangerous to tissues.
Many compounds in foods are weak acids, including CITRIC ACID, ACETIC ACID, and TARTARIC ACID. Several weak acids are used as FOOD ADDITIVES, including benzoic acid, CARBONIC ACID, and alginic acid. As food additives and recipe ingredients, weak acids add tartness to foods. Weak acids are common intermediates, products of cellular processes that sustain life, including LACTIC ACID, KETONE BODIES, PYRUVIC ACID, acetic acid, FATTY ACIDS, SUCCINIC ACID, citric acid, even the nucleic acids DNA and RNA. GLUTAMIC ACID and ASPARTIC ACID (two common AMINO ACIDS) are classified as acidic amino acids, and are more acid than most.
In the body, weak acids characteristically have lost all their hydrogen ions and exist as a family of anions (negatively charged ions) classified as “conjugate bases” because they have been completely neutralized by the buffer systems of blood. In the blood, lactic acid exists as its anion, lactate; acetoacetic acid (a ketone body) as acetoacetate; citric acid as citrate, and so on. Often the names of acids and their anions are interchanged in nutrition literature.

What is achlorhydria?

A condition resulting from the lack of STOMACH ACID. DIARRHEA, stomach discomfort, and bloating are common symptoms of achlorhydria, which has serious effects. It can lead to MALNUTRITION, even when the diet is well balanced, because achlorhydria drastically reduces the efficiency of DIGESTION. A chronic MALABSORPTION syndrome leads to deficiencies of VITAMIN B12, CALCIUM, IRON, and other nutrients and sets the stage for chronic FATIGUE, OSTEOPOROSIS, ANEMIA, and serious infections. Although causes of achlorhydria are unknown, lowered stomach acid production is associated with anemia, stomach inflammation, CELIAC DISEASE, diabetes, lupus, myasthenia gravis, rheumatoid ARTHRITIS, and some forms of cancer. Limited stomach acid production, not the absence of stomach acid, is termed HYPOCHLORHYDRIA. It is not as severe a condition as achlorhydria, although unless corrected, the ensuing malabsorption syndrome can have similar, detrimental longrange effects on health. In either situation patients may be advised to take supplemental hydrochloric acid in the form of BETAINE HYDROCHLORIDE or glutamic acid hydrochloride with meals to enhance digestion. These supplements should be used with medical supervision because of the danger of overdosing.
(

What is acetoacetic acid (acetoacetate)

The most prevalent of the KETONE BODIES, which are acids produced by the liver. Acetoacetic acid is a useful fuel; it is readily oxidized by the heart and brain for the production of ATP, the energy currency of cells.
Though small amounts of ketone bodies are normally produced by liver metabolism, an excessive buildup of acetoacetic acid and its derivative, BETA HYDROXYBUTYRIC ACID, in the blood (ketonemia) can occur during excessive fat breakdown, when the liver cannot completely oxidize massive amounts of fatty acids released from fat (ADIPOSE TISSUE). Conditions conducive to excessive acetoacetic acid production include STARVATION (prolonged FASTING), crash DIETING, uncontrolled DIABETES MELLITUS, and chronic ALCOHOLISM.
Ketone body production serves an important role in the physiologic adaptation to starvation. With prolonged starvation, the blood levels of ketone bodies rise, and more of them cross the BLOOD-BRAIN BARRIER to be taken up by nerve tissue, where they are burned for energy. Consequently, the brain requires less blood glucose (blood sugar) for energy at a time when this fuel is at a premium. The sustained build-up of acetoacetic acid in the blood (KETOSIS) can acidify the blood, leading to metabolic ACIDOSIS, and alter the acid-base balance of the body, a potentially dangerous condition.

What is acetic acid?

During fermentation, certain bacteria produce acetic acid by oxidizing alcohol when exposed to air. VINEGAR contains 4 percent to 6 percent acetic acid, which gives vinegar its characteristic sour taste. As vinegar, acetic acid is a common ingredient in food preparation.
One of the simplest organic acids, acetic acid contains only two carbon atoms. It is classified as a weak acid because it is only partially ionized, unlike strong mineral acids, such as hydrochloric acid.
Acetic acid plays a pivotal role in metabolism. To be metabolized, acetic acid must be activated as acetyl CoA, in which acetic acid is bound to a carrier molecule, COENZYME A, which is in turn derived from the B vitamin PANTOTHENIC ACID. Metabolic pathways that oxidize fatty acids, carbohydrate, and amino acids for energy, all yield acetyl CoA, the common intermediate by which carbons from these fuels enter the KREB’S CYCLE to be oxidized to carbon dioxide. Alternatively, acetyl CoA can be used as a building block. It forms saturated fatty acids, cholesterol, and ketone bodies. Nerve cells can use it to form the NEUROTRANSMITTER, ACETYLCHOLINE. Tissues combine acetic acid with amino sugars to form a family of sugar derivatives like Nacetylglucosamine and N-acetylgalactosamine that help define recognition sites on the surface of cells and blood group specificities, such as the A, B, O, and Lewis blood groups used in blood typing.

Acesulfame-K (acesulfame potassium; Sunett)

This non-caloric, ARTIFICIAL SWEETENER tastes approximately 200 times sweeter than table sugar (SUCROSE) and lacks the bitter aftertaste of SACCHARIN. The United Nations Food and Agriculture Organization endorsed acesulfame-K as a satisfactory artificial sweetener in 1983. Acesulfame-K was approved in 1988 by the U.S. FDA as a sugar substitute to be used in packets or as tablets and now is approved for use in chewing gum and in powdered drink mixes. Unlike ASPARTAME, acesulfame-K can be used in cooking because it does not break down at oven temperatures. Blending Sunett with other low-calorie sweeteners creates a beverage with a more sugarlike taste than one sweetened with any single low-calorie sweetener.
The Center for Science in the Public Interest has raised questions about Sunett’s safety, saying a few tests on rats indicated a possibility of cancer, although this was not proof that the sweetener could cause cancer. The Calorie Control Council counters that the safety of acesulfame potassium has been confirmed by more than 90 studies, and it is endorsed by a committee of the World Health Organization. Theoretically, it would not be expected to be absorbed by the body. Nonetheless, some studies suggest that large doses raise blood CHOLESTEROL levels in diabetic laboratory animals and increase the number of lung and mammary tumors in other animals.