Betty is a Registered Dietitian who earned her B.S. degree in Food and Nutrition from Marymount College of Fordham University and her M.S. degree in Clinical Nutrition from New York University. She is the Co-Director and Director of nutrition for the New York Obesity Research Center Weight Loss Program.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Vitamin A is a fat-soluble vitamin that is broken down into two categories: preformed vitamin A comes from animal foods, and provitamin A carotenoid comes from plant foods.
Vitamin A serves many functions:
helps regulate the immune system to prevent and fight infections
helps form and maintain healthy teeth, skin, and tissues
produces the pigments in the retina of the eye
promotes good vision
How much do I need to consume?
The Recommended Dietary Allowances (RDA) for vitamin A are listed as International Units (IU) of Retinol Activity Equivalents (RAE). This is done to account for the different actions of both forms of vitamin A.
RDA for vitamin A:
Age
Males
Females
Pregnancy
Lactation
1 to 3 yrs
1,000 IU
1,000 IU
N/A
N/A
4 to 8 yrs
1,320 IU
1,320 IU
N/A
N/A
9 to 13 yrs
2,000 IU
2,000 IU
N/A
N/A
14 to 18 yrs
3,000 IU
2,310 IU
2,500 IU
4,000 IU
19+
3,000 IU
2,310 IU
2,565 IU
4,300 IU
There is insufficient information to establish an RDA for vitamin A for infants. In this case, an Adequate Intake (AI) has been established:
Age
Males and Females
0 to 6 months
1,320 IU
7 to 12 months
1,650 IU
What are sources of vitamin A?
Vitamin A can be found in animal and plant foods. The animal food sources are better absorbed and used by the body than the plant sources. There are also many foods that are fortified and enriched with vitamin A.
The content of vitamin A in animal and plant foods (from beta-carotene):
Vitamin A is stored in the liver, so there is a supply that can be used during short-term periods when intake is not adequate to meet your needs. People with medical conditions that interfere with the absorption of vitamin A may need to take a supplement. These conditions include celiac disease, Crohn's disease, inflammatory bowel disease, and pancreatic disorders. Because vitamin A can be toxic at high levels, it's best to discuss supplements with your physician.
What happens if I don't have enough vitamin A?
Early vitamin A deficiency leads to impaired night vision, and advanced vitamin A deficiency can lead to corneal ulcers, xerophthalamia (dry eye), scarring, night blindness or total blindness. In developing countries, vitamin A deficiency is an important cause of blindness among children. Children with vitamin A deficiency are also more likely to develop diarrhea and respiratory infections than children who are not vitamin A deficient. Vitamin A deficiency is rare among healthy adults in the United States.
Vitamin A deficiency can also be a problem for people with Crohn's disease, celiac disease, pancreatic disorders, and people who do not consume animal foods.
Is there such a thing as too much vitamin A?
When excess amounts of vitamin A are being stored in your body, the condition is called hypervitaminosis A. The harmful effects of hypervitaminosis A are birth defects, reduced bone density that may result in osteoporosis, central nervous system disorders, and liver abnormalities.
Acute vitamin A toxicity may result from consuming very large quantities of vitamin A over a short period of time. The symptoms are nausea, vomiting, irritability, drowsiness, altered mental status, anorexia, abdominal pain, blurred vision, muscle pain with weakness, and/or headache. Elderly people and people who drink alcohol heavily are more susceptible to vitamin A toxicity.
The Institute of Medicine states that "beta-carotene supplements are not advisable for the general population," although they also state that this advice "does not pertain to the possible use of supplemental beta-carotene as a provitamin A source for the prevention of vitamin A deficiency in populations with inadequate vitamin A."
The Tolerable Upper Limit (UL) for vitamin A is:
Age
Males and Females
Pregnancy
Lactation
0 to 1 year
2,000 IU
N/A
N/A
1 to 3 years
2,000 IU
N/A
N/A
4 to 8 years
3,000 IU
N/A
N/A
9 to 13 years
5,610 IU
N/A
N/A
14 to 18 years
9,240 IU
9,240 IU
9,240 IU
19+ years
10,000 IU
10,000 IU
10,000 IU
In the ATBC trial, subjects given beta-carotene had a higher incidence of lung cancer than subjects not given beta-carotene. The Institute of Medicine did not set ULs for carotene or carotenoids. However, the recommendation is that beta-carotene supplements are not advisable for the general population.
There are many symptoms involved in the 1st, 2nd and 3rd trimesters of pregnancy. The first early pregnancy symptom is typically a missed period, but others include breast swelling and tenderness, nausea and sometimes vomiting, fatigue and bloating. Second trimester symptoms include backache, weight gain, itching, and possible stretch marks. Third trimester symptoms are additional weight gain, heartburn, hemorrhoids, swelling of the ankles, fingers, and face, breast tenderness, and trouble sleeping. Read more to learn about recommended procedures and tests for each stage of a healthy pregnancy.
There are many causes of scalp hair loss. This featured article covers the common ones such as patchy hair loss (alopecia areata, trichotillomania, and tinea capitis), telogen effluvium, and androgenetic alopecia (male-pattern baldness, female-pattern baldness).
Learn about osteoporosis, a condition characterized by the loss of bone density, which leads to an increased risk of bone fracture. Unless one experiences a fracture, a person may have osteoporosis for decades without knowing it. Treatment for osteoporosis may involve medications that stop bone loss and increase bone strength and bone formation, as well as quitting smoking, regular exercise, cutting back on alcohol intake, and eating a calcium- and vitamin D-rich balanced diet.
Osteopenia is a bone condition characterized by bone loss that is not as severe as in osteoporosis. Bone fracture is the typical symptom of osteopenia, though the condition may be present without symptoms. Treatment involves lifestyle modifications (quitting smoking, not drinking in excess) and ensuring an adequate intake of vitamin D and calcium.
Hypercalcemia is a condition in which calcium levels in the blood are elevated. Hypercalcemia is associated with other conditions such as hyperparathyroidism, lung cancer, breast cancer, kidney failure, and elevated levels of vitamin D. Symptoms of hypercalcemia include constipation, nausea, abdominal pain, kidney stones, to name a few. Treatment depends on the cause of hypercalcemia.
Pregnancy planning is important to help prevent exposure of the mother and fetus to potentially harmful medications and substances during the early days, and throughout the pregnancy. Nutritional planning, prevention of birth defects, conditions such as high blood pressure, heart disease, diabetes, and kidney disease need careful monitoring. Gestational diabetes, preeclampsia, and pregnancy induced hypertension are conditions that may arise during pregnancy. Immunizations, inherited disorders, exercise, air travel, intercourse, and birth control are important factors to consider when planning a pregnancy.
Rickets is caused by a deficiency of vitamin D, calcium or phosphate. Infants and children who are exclusively breastfed, have dark skin, and infants born to mothers who are vitamin D deficient are most at risk for developing rickets. Symptoms and signs of rickets include bone pain, delayed teeth formation, short stature, skeletal deformities (bowlegs, abnormally shaped skull), and decreased muscle strength. Treatment of rickets depends upon the cause, but the first step usually involves correcting any abnormal levels of calcium, phosphate, or vitamin D with supplements.
Vitamin D deficiency has been linked with rickets, cancer, cardiovascular disease, severe asthma in children and cognitive impairment in older adults. Causes include not ingesting enough of the vitamin over time, having limited exposure to sunlight, having dark skin, and obesity. Symptoms include bone pain and muscle weakness. Treatment for vitamin D deficiency involves obtaining more vitamin D through supplements, diet, or exposure to sunlight.
Enjoying a healthy diet helps to prevent diseases. A good diet also helps to control celiac disease, diabetes, and high blood pressure and maintain health by preventing loss of bone mass, muscle strength, and vitamin deficiencies.
Children's health is focused on the well-being of children from conception through adolescence. There are many aspects of children's health, including growth and development, illnesses, injuries, behavior, mental illness, family health and community health.
The importance of a healthy lifestyle in disease prevention is widely understood and most people know that lifestyle changes and choices can be critical to good health. Yet, few practice healthy behaviors that constitute healthy living.
Disease prevention in men includes routine screening tests that are part of basic prevention medicine. Take an active role in your own health care and discuss screening tests with your doctor early in life. Age of screening and timing of screening depends upon the condition being assessed.
Disease prevention in women includes screening tests that are a basic part of prevention medicine. All screening tests
are commonly available through your general doctor. Some specialized tests may be available elsewhere.
Setting a good example for your children when it comes to diet and exercise will help them to make healthy decisions about nutrition and fitness. Eating calcium-rich foods and performing weight-bearing exercise will help your children prevent osteoporosis and fractures later in life.
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