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 D is probably most well-known for being the "sunshine vitamin." The ultraviolet rays from the sunlight strike the skin, causing vitamin D to be made. It can also be found in food and supplements. This is one of the four fat-soluble vitamins. That means that it's stored in the body's fatty tissue and can build up to toxic levels with excessive consumption.
The major function of vitamin D is to maintain optimal blood levels of calcium and phosphorus. Studies have shown that it provides protection from hypertension, cancer, osteoporosis, type 1 diabetes, and several autoimmune diseases.
How much do I need to consume?
The recommendations for vitamin D are listed as an Adequate Intake in micrograms (mcg) and International Units (IU):
Age
Vitamin D
Birth to 13 years
5 mcg (200 IU)
14 to 18 years
5 mcg (200 IU)
19 to 50 years
5 mcg (200 IU)
51 to 70 years
10 mcg (400 IU)
71+ years
15 mcg (600 IU)
What are sources of vitamin D?
The sunshine vitamin got its name from the fact that the sun helps our body produce vitamin D. The concern about skin cancer has caused many people to avoid unprotected exposure to the sun. Fortunately, it is possible to consume enough vitamin D in your diet, so it is not necessary to risk the dangers of skin cancer by exposing yourself to the sun. For those who do rely on the sun as one of their sources, there are many factors that will impact how much you need. The season, time of day, cloud coverage, smog, amount and SPF of sunscreen, geographic latitude, and melanin content of your skin are all possible barriers. It can take anywhere from
five to 30 minutes of sun on unexposed skin between the hours of 10 a.m. and 3 p.m. at least twice a week.
The foods that naturally contain vitamin D are seafood, mushrooms, and egg yolks. Dietary sources of vitamin D are:
When diet is not enough, you may need to take a supplement to help you reach the desired intake of vitamin D. As you will see, vitamin D can be toxic at high levels, so the goal is to reach the appropriate level, not exceed it.
The two primary types of vitamin D supplements are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Most experts believe that vitamin D3 is the ideal choice for these reasons:
Vitamin D3 is the most potent form, it's more stable on the shelf, and it's less toxic than D2.
Vitamin D3 is the one that is synthesized when the sun hits your skin, so it's considered to be the most natural.
Most of the research that has been done on vitamin D and its health benefits has used vitamin D3.
What happens if I don't have enough vitamin D?
You can have blood tests done to determine if you are deficient in vitamin D. Your 25(OH)D level will be measured. Most experts agree that 25(OH)D level of <20 ng/mL is considered to be vitamin D deficiency, whereas a 25(OH)D level of 21-29 ng/mL is considered to be insufficient.
Research has shown strong relationships between lower rates of chronic diseases and higher levels of vitamin D. The most well-known disease related to vitamin D deficiency is rickets. Rickets is the disease that was found to be cured by consuming cod liver oil in the early 20th century. Rickets causes soft, weak bones in children, resulting in skeletal deformities (bowed legs), impaired growth, bone pain, dental problems, and fragile bones. Unfortunately, rickets has still been seen in children not being fed an adequate amount of vitamin D. In adults, vitamin D deficiency can lead to osteoporosis and osteomalacia (both are conditions of weakened bones).
There are several other factors that can contribute to a deficiency in vitamin D:
Age: People over 50 years old have a decreased ability to synthesize and absorb vitamin D. This occurs regardless of the amount of sun exposure time.
Medical conditions: Vitamin D requires fat for absorption, so anyone with a medical condition that reduces the ability to absorb dietary fat can be at risk for a deficiency. It is important to have vitamin D levels monitored in people with conditions such as Crohn's disease, celiac disease, cystic fibrosis, pancreatic enzyme deficiency, and surgical removal of any part of the stomach or intestines.
Obesity: Research has shown lower vitamin D concentrations in overweight and obese individuals. One possible reason for this is that vitamin D gets absorbed by fat tissue and is not easily absorbed in the bloodstream.
Sun exposure: The ultraviolet rays from the sun have served as a source of vitamin D over the years. Due to the danger of skin cancer, many people have cut back on their exposure to the sun and have begun using sunscreen when they are being exposed, so this can contribute to lower levels if adjustments are not made to compensate for this loss via dietary sources and/or supplements.
Skin pigmentation: There is more melanin in darker-skinned individuals. Melanin blocks the ultraviolet rays and interferes with vitamin D synthesis.
Are there any dangers to consuming too much vitamin D?
Consuming excessive amount of vitamin D can pose health problems. This is most likely to occur from taking supplements or high doses of cod liver oil. There is no danger of vitamin D toxicity from sun exposure. Symptoms of toxicity can be nausea, poor appetite, weakness, weight loss, constipation, and high blood levels of calcium. A blood level of over 200 ng/mL for vitamin D, measured as 25(OH)D, can be potentially toxic. For this reason, the tolerable upper intake (UL) for vitamin D has been set at 2,000 IU (50 mcg) per day for ages 1 and above. The UL for birth to 12 months is 1,000 IU (25 mcg) per day.
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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