Acrylamide and Human Health

A chemical used in making plastics, textiles, and dyes and in purifying drinking water. Short-term exposure above safe limits (maximum contaminant levels) set by the Environmental Protection Agency (EPA) causes damage to the central nervous system. Long-term exposure can cause paralysis and possibly cancer. The chemical has been shown to cause cancer in laboratory animals. In 2002 the World Health Organization (WHO) convened an emergency meeting of food safety and health experts after a team of Swedish scientists reported that some starch-based foods, like potato CHIPS, FRENCH FRIES, and some BREAKFAST CEREALS and BREADS, contain high levels of acrylamide. The amount of the chemical found in a large order of fast-food french fries was at least 300 times above EPA safe limits for drinking water. Additional studies in Norway, Great Britain, Switzerland, and the United States reached similar results.
Acrylamide apparently forms in some starchy foods when they are baked or fried at high temperatures. Raw or boiled samples of these foods, such as potatoes, test negative for the chemical. Research on the health effects of acrylamide in food is ongoing. For the time being, most health experts have stopped short of advising consumers to avoid the risky foods or change their cooking methods.

Understanding Acidosis

The acidification of the blood and other body fluids. This condition can be due to acid accumulation or to the loss of bicarbonate buffering capacity from kidney disease. The pH of blood is tightly regulated; the normal range is between pH 7.3 and 7.4. A drop in blood pH below pH 7.3, which corresponds to increased hydrogen ion concentration, could signal excessive acidity of the blood (ACIDEMIA). Homeostatic mechanisms (the body’s regulatory system of checks and balances) help prevent acidosis. Bicarbonate and serum proteins take up hydrogen ions to neutralize excessive acid rapidly, while the kidneys more slowly compensate for acid production by excreting surplus hydrogen ions. Prolonged acidosis requires medical attention because it slows down many vital functions, including nerve transmission and heart muscle contraction. Symptoms of acidosis include nausea, vomiting, DIARRHEA, headache, rapid breathing, and, eventually, convulsions.
Two forms of acidosis are recognized: metabolic and respiratory. Metabolic acidosis can occur when metabolic acids accumulate excessively. For example, when the body burns FAT at a high rate, the liver converts FATTY ACIDS to KETONE BODIES, acidic substances. This condition may occur during crash DIETING and FASTING or in a person suffering from uncontrolled DIABETES MELLITUS or chronic ALCOHOLISM.
Excessive ingestion of acids, such as in aspirin poisoning, also causes acidosis. Metabolic acidosis can also result from vomiting or diarrhea, which cause excessive loss of ELECTROLYTES like BICARBONATE and upset the acid/base balance.
Renal disease may prevent the kidneys from adequately correcting acid production.
Respiratory acidosis can occur when breathing does not adequately remove carbon dioxide. Shallow breathing, associated with respiratory disease, can cause excessive CARBON DIOXIDE in the lungs, in turn causing carbon dioxide blood levels to rise and upset the bicarbonate buffer system of the blood.

Acidophilus (Lactobacillus acidophilus) and Nutrition

A species of the bacterium Lactobacillus that produces lactic acid by fermenting LACTOSE (milk sugar). This organism in the upper intestinal tract forms a symbiotic relationship with its human host. Other acid producing bacteria, including BIFIDOBACTERIA, are predominant in the lower intestine. Acidophilus is a member of the normal intestinal microflora, the so-called friendly bacteria that produce nutrients like BIOTIN and VITAMIN K. Acidophilus and other Lactobacillus species help balance the digestive system by maintaining conditions that inhibit the growth of yeasts like CANDIDA ALBICANS, as well as potentially dangerous bacterial species. Without beneficial bacteria to control them, such opportunistic microorganisms can multiply rapidly, leading to a full-blown infection.
A variety of conditions can drastically lower or eliminate the intestinal acidophilus population.
Treatment with broad-spectrum antibiotics (such as tetracycline) imbalances gut microecology because these antibiotics destroy both benign and disease producing bacteria. More generally, an unhealthful lifestyle and a diet high in SUGAR and PROCESSED FOODS also adversely affect beneficial intestinal bacteria.
Acidophilus is a common food supplement that may help repopulate the gut with beneficial bacteria to prevent hard-to-control yeast infections; to break down milk sugar for those with LACTASE DEFICIENCY; to control travelers’ DIARRHEA; to relieve CONSTIPATION; to treat vaginitis (when administered as acidophilus douches); and to decrease the production of potential CARCINOGENS by certain bacteria populating the gut.

Food and acid indigestion (heartburn, esophageal reflux, gastric reflux)

A condition characterized by a burning pain near the stomach. Typically, this occurs an hour or so after a heavy (fatty) meal and is often relieved by taking ANTACIDS or by drinking MILK. Acid indigestion is the most common gastrointestinal complaint in the United States; one in 10 Americans suffer daily attacks. The pain associated with acid indigestion is caused by STOMACH ACID backing up into the ESOPHAGUS, the region of the throat connecting the mouth with the stomach. Acid indigestion can be caused by air gulped when swallowing large bites of food, which can keep the passageway open. Some food allergies and food sensitivities may trigger acid indigestion by relaxing the sphincter muscles that normally seal off the stomach juices from the esophagus after eating. Although the stomach lining is protected from acid by mucus, the unprotected esophagus is irritated by repeated exposure to acid.
To prevent acid indigestion, patients should eat slowly and chew food thoroughly, avoiding foods and beverages that cause adverse reactions. Common examples include fatty foods, CHOCOLATE, COFFEE, CITRUS FRUIT, and alcoholic beverages. Also
patients should consult a physician for any chronic stomach pain because what feels like acid indigestion may actually be inadequate stomach acid (HYPOCHLORHYDRIA). Patients should seek immediate medical attention if experiencing a crushing pain in the middle of the chest that extends to the left arm, since these symptoms could indicate a heart attack.

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.