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Sodium
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.
Other Resources :
The
More You Know About Minerals
The
More You Know About Nutrition
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.
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