Vitamins, Minerals and Dietary Supplements
What is sodium?
A silvery-white mineral, sodium is one of the most abundant elements
in nature. It is usually seen in combination with one or more elements
and is chemically very active. About half of the sodium found in the body
is in the soft tissues.
Why do we need it?
Sodium plays an essential role in the regulation of blood pressure and
blood volume. It also assists with proper muscle contraction and the transmission
of nerve impulses. Moderate sodium intake increases resistance to heat
cramps and heat stroke, especially during periods of excessive fluid loss
through sweating.In addition, manganese plays an important role in the
synthesis of cholesterol and fatty acids, and is essential for the utilization
of choline, thiamin, biotin, and vitamins C and E. It helps activate enzymes
that regulate blood sugar, energy metabolism and function of the thyroid
gland.
How much sodium should I take?
According to the National Academy of Sciences, the recommended daily
allowance (RDA) for sodium is between 1,100-3,300 milligrams/day.
What are some good sources of sodium?
Sodium occurs naturally in nearly every food, from milk and beets to
celery. It is most readily available in flavorings such as table salt,
garlic salt, onion salt and soy sauce. One teaspoon of table salt contains
approximately 2,300 milligrams of sodium. Sodium is also added to various
food products. Added forms include monosodium glutamate, sodium nitrite,
baking soda (sodium bicarbonate) and sodium benzoate. Processed meats
such as bacon, sausage and ham, and canned soups and vegetables all contain
added sodium. Fast foods are generally very high in sodium.
What can happen if I don't get enough sodium?
Sodium deficiency can be attributed to starvation, vomiting, diarrhea,
extreme sweating, or any condition with excessive fluid loss. Symptoms
of sodium deficiency include intestinal gas, weight loss, short attention
span, vomiting, heart palpitations and muscle weakness. Deficiency can
cause a buildup of acids in the body, which can lead to arthritis, rheumatism
and neuralgia.
What can happen if I take too much?
Excessive sodium intake can cause a loss of potassium in the urine, leading
to potassium deficiency. Symptoms of excess sodium include edema, dizziness,
and swelling of the legs and face. Excessive salt intake has also been
linked to hypertension, and diets high in sodium may increase the likelihood
of liver, heart and kidney disease.
References
- Recommended Dietary Allowances, 10th ed. Washington,
D.C.: National Academy Press, 1989.
- Beard TC, Blizzard L, OBrien DJ, Dwyer T. Association
between blood pressure and dietary factors in the dietary and nutritional
survey of British adults. Arch Intern Med 1997;157:234-238.
- Cappuccio FP, Markandu ND, Carney C, Sagnella GA,
MacGregor GA. Double-blind randomised trial of modest salt restriction
in older people. Lancet Sep 1997;350(9081):850-4.
- Graudal NA, et al. Effects of sodium restriction on
blood pressure, renin, aldosterone, catecholamines, cholesterols and
triglyceride. JAMA 1998;279:1383-1391.
- Rollnik JD, Mills PJ, Dimsdale JE. Characteristics
of individuals who excrete versus retain sodium under stress. J Psychosom
Res May 1995;39(4):499-505.
- Carey OJ, Locke C, Cookson JB. Effect of alterations
of dietary sodium on the severity of asthma in men. Thorax Jul
1993;48(7):714-8.
