Recommended Vitamin C, D, E & Mineral Supplements Dosages
Vitamin E and the Battle against Cancer or Cardiovascular Disease
For more information on the related topic of health supplements, please see our 10 part series of articles beginning with the article: "Herbs and Dietary Supplements-Part I St. John's Wort"
(10/23/13)- The results of an analysis of studies done to determine if ingesting vitamin D supplements could prevent osteoporosis in middle-aged adults concluded that it did not do so. Dr. Ian R. Reid, the lead author of the study, and a professor of medicine at the University of Auckland in New Zealand stated: “But for healthy people focused on osteoporosis prevention, vitamin D does not make a positive contribution.”
The results of the analysis that was published online in The Lancelet, included 23 randomized trials that measured the effect of vitamin D on bone density at four sites- spine, neck, hip and forearm. There were over 4,000 generally healthy people in the trial with an average age of 59.
The dosages of vitamin D that were taken by the subjects varied from 500 units a day to 800 or more, given at varying schedules. Some of the participants received calcium as well
(11/7/12)-Data was released from a study whose results were announced in October that showed that the taking of daily multivitamins did not cut the risk of heart attack or stroke in 14,500 men who were followed for more than a decade.
There was however a small reduction in cancerous conditions. The trial, called the Physicians Health Study II enrolled 14,641 male U.S. physicians, ages 50 and older, when the study began. About 700 of them had heart disease at the start of the study.
Half the study group received a multivitamin, while the other half received a placebo. Researchers followed the study groups for 11 years, measuring cardiovascular events, strokes and deaths.
There were 1,732 major cardiovascular events and 2,757 deaths during the study. The researchers concluded that event rates were about the same for both groups involved in the study.
The findings were presented at the American Heart Association’s annual meeting and published online in the Journal of the American Medical Association.
The study was partially funded by the National Institutes of Health. The multivitamin used in the study was Pfizer & Co'.s Centrum Silver. In addition to cancer and heart disease, the researchers also looked at whether multivitamins affected cognitive decline and eye disease, but no results have been announced on these issues.
(2/9/11)- For good bone health growth, vitamin D and calcium go hand in hand. The Institute of Medicine issued a statement in November that contained recommended levels of intake and warned that excessive intake of these supplements may be harmful for bone growth. Vitamin D is needed for calcium to be absorbed from the digestive tract.
The institute's expert committee, which included bone specialists, concluded that most people do not need supplements, and warned of serious health risks from the high dosages that some people are now taking.
The increased risk from taking high dosages of either calcium of vitamin D supplements include kidney stones and heart disease, and the very falls and fractures that vitamin D is meant to protect against
For daily calcium intake, the institute now recommends 1,000 milligrams for children 4 to 8, women and men 19 to 50, and men 51 to 70; 1,300 milligrams for children 9 to 18; and 1,200 milligrams for women 51 and older and men 71 and older.
The upper limit of safety is 2,000 milligrams a day for men and women over 51. Because of their loss of estrogen, women are especially vulnerable to loss of bone density at menopause..
Most calcium supplements now also include vitamin D, supplying about 250 to 300 international units in two tablets. The Institute of Medicine recommends 600 units a day for everyone from age 1 to 70 and 800 units for men and women 71 and older, with a safe upper limit for everyone over the age of 9 of 4,000 units.
The body gets most of its vitamin D from skin exposed to the ultra-violet B radiation in sunlight. Unprotected skin on the arms and legs may need about 15 minutes of sun exposure a day in spring, summer and fall to make enough of the vitamin. This production is however effectively blocked if you follow current advice to prevent skin cancer and wrinkles by always covering up or using ample amounts of sunscreen.
Milk is fortified with vitamin D at a level of 400 units per quart, and some yogurts have it as well (check the label). Many breakfast cereals are also now fortified with vitamin D. The only naturally rich dietary sources are oily fish like salmon and mackerel, egg yolks, liver and fish liver oil.
(12/8/10)- If you thought you were confused before, imagine how confused you would be after reading the headlines of two articles on the same day, in two different New York City newspapers. The one in the New York Times by Gina Kolata was titled "Extra Vitamin D and Calcium Aren't Necessary, Report Says", and the other in the Wall St. Journal by Melinda Beck was entitled: "Triple That Vitamin D Intake, Panel Prescribes".
The article by Ms. Kolata states: "The very high levels of vitamin D that are often recommended by doctors and testing laboratories-and can be achieved only by taking supplements-are unnecessary and could be harmful, an expert committee says. It also concludes that calcium supplements are not needed."
The article by Ms. Beck states: "A long awaited report from the Institute of Medicine to be released Tuesday triples the recommended amount of vitamin D most Americans should take very day to 600 international units from 200 IUs set in 1997."
Both articles are discussing the same report that was issued by the Institute of Medicine.The Institute of Medicine is an arm of the National Academy of Sciences that sets governmental nutritional levels.
The new recommendations, which cover the United States and Canada, sets a level of 600 IUs of vitamin D daily for infants through adults age 70, and 800 IUs after age 71. The panel also raised the upper limits of daily intake of vitamin D to 4,000 IUs for adults, from 2,000 IUs previously.
Milk fortified with vitamin D contains about 40 IUs per cup.
The panel also issued new recommendations for daily calcium intake, ranging from 700 milligrams for children aged 1 to 3 up to 1,200 for women 51 and older. For men older than 50 and under 70 the recommended level was 1,000 milligrams.
The panel also concluded that for 97% of the population, a blood level of 20 nanograms of vitamin D per millimeter is sufficient.
According to Ms. Kolata's article, Dr. Clifford J. Rosen, a member of the panel and an osteoporosis expert at the Maine Medical Center Research Institute said: "For most people, taking extra calcium and vitamin D supplements is not indicated".
The National Business Journal estimate that sales of vitamin D has grown faster than those of any other supplement. Sales rose 82% from 2008 to 2009 to $430 million.
The 14 member expert committee was convened by the Institute of Medicine, an independent non-profit scientific body, at the request of the United States and Canadian governments.
(2/25/09)- Are there positive advantages for one's health in taking "megadoses" of essential vitamins as proposed by Linus Pauling, the Nobel-Prize-winning biochemist 40 years ago? For those of us who believe in the beneficial side of the argument, and who practice what they preach, there is no doubt that having a positive mental attitude as to it "helping" should continue to ingest to their hearts content. Although there have been some studies that indicated that "megadosing" can be harmful to your health, there is no credible scientific information that this is so.
On the other hand there have been several studies recently that have failed to show that taking extra vitamins, in pill form, help prevent chronic disease or prolong life.
The results of a recent study that tracked over 161,000 older women who were in the Women's Health Initiative for 8 years, that was published in The Archives of Internal Medicine found that there were no health benefits as a result of "megadosing".
In October 2008 a study of 35,000 men concluded that there were no benefits towards lowering the risk of prostate cancer shown for individuals who took high doses of vitamin E and selenium. Dr. Eric Klein, national study coordinator for the study, and who is also chairman of the Cleveland Clinic's Glickman Urological and Kidney Institute stated: "The public's belief in the benefits of vitamins and nutrient is not supported by the available scientific data."
In another study, the results of which were published last year, that tracked almost 15,000 male physicians for a decade found that there was no difference in cancer or heart disease rates among those taking vitamins E and C compared with those taking a placebo.
(4/3/05)- According to a study that was led by researchers at McMaster University and Hamilton Health Sciences in Ontario, Canada people who took large dosages of Vitamin E for an average of 7 years did not see a reduction in the rate of cancer or cardiovascular diseases. The study was designed to determine whether people who took 400 IUs of vitamin E daily had a lower rate of heart related events or cancer, than those who did not take such large dosages.
Daily multivitamins contain much smaller amounts of vitamin E, ranging from 30 to 45 Ius. Patients in the study had diabetes or vascular disease and were at least 55 years old when the study began in 1993. There were slightly over 9,000 patients enrolled in the original study.
The first part of the study followed patients from January 1993 through January 1999. The results of that study were that taking large dosages of vitamin E did not decrease the risk of cancer or cardiovascular events. That original study was then extended through May 2003, and involved about 4,700 patients. The study concluded that in fact patients taking large dosages of vitamin E were 13% more likely to have heart failure and related hospitalizations than those in the placebo group.
Although the finding of slightly increased risk from taking the vitamin E the researchers concluded that this should not be taken as a definite conclusion. "Although this finding could be due to chance, several factors lead us to believe it may be real," they wrote.
(12/15/03)-Should you be taking a multivitamin pill? Many of us ask ourselves this question since we read and hear so much about how a single pill can help to improve your health. Most experts feel that healthy adults who eat a varied diet don't need vitamin supplements. Others argue that even healthy adults eating habits leave out certain important helpful nutrients.
We can not answer this question for you but we can at least explain to you what a multivitamin pill does contain so that you can help to judge for yourself if you should take one of these pills. A multivitamin should contain 100% of the FDA's recommended daily value (DV) for vitamins A (some form of beta-carotene), B1 (thiamin), B2 (riboflavin), B3 (niacin), B6, B12, C, D, E and folic acid. It should also have some vitamin K although people who are on blood thinners should try to avoid taking vitamin K.
The multivitamin pill should also contain minerals, so look for copper, magnesium and selenium. Since calcium is so bulky the multivitamin pill usually does not contain 100% of the DV for this mineral. There is no evidence that taking more than 100% of the recommended DV will make you any healthier. Taking more than the recommended dose for vitamin B and vitamin C, which are known as the "water soluble" vitamins won't harm you since your body will excrete whatever it does not need. Taking more than the recommended DV of vitamins A, D and K can cause harm because they build up in the body and can be toxic. Vitamins A, D and K are what are known as "fat soluble" vitamins.
There is an excellent site from the Institute of Medicine where you can check out the safe upper limits for all vitamins and minerals. It can be found at www.iom.edu. Click on Programs, then Food and Nutrition Board. To see more on these topics please see our articles:
Please keep in mind that multivitamins can react with certain medications that you may be taking so check with your medical professional before taking any multivitamin. To prevent stomach upset and to improve absorption take the multi vitamin when you are having some food with it.
The U.S. Preventive Services Task Force, said it had examined several dozen studies on vitamins, and found that the results were "inadequate or conflicting." It concluded therefore that there isn't enough evidence to either recommend or reject the use of vitamin supplements as a way to reduce the risk of cancer and heart disease.
The anti-oxidant vitamins, which include vitamins A, C and E have been promoted for their benefit in preventing the heart-damaging effects of oxygen on arteries and the cell damage that might spur some kinds of cancer. Some researchers now believe that the anti-oxidant vitamins only work when they are in food rather than when taken as supplements in the form of pills.
A U.S. Government research team from the National Institute of Health has reported in the April 21, 1999 edition of the Journal of the American Medical Association that the daily recommended allowance of Vitamin C intake be increased from 60 milligrams to between 100 to 200 milligrams per day. The team headed by Dr. Mark Levine has determined that the increased dosage increases the body's ability to fight against cancer when taken in the form of fruits and vegetables.
Their evidence points to the fact that 5 servings a day of fruit and vegetables may help prevent cancer. So far they have not been able to determine if the benefit results from the Vitamin C itself or from the components of the food. They did however caution that 200 milligrams was the maximum that the body could absorb on a daily basis. The National Academy of Sciences Food and Nutrition Board is reviewing whether or not to increase the 60-milligram per day level that has been the accepted belief since 1980.
More than 20% of United States adults consume a vitamin or mineral supplement daily. A majority of supplement users (75%) consume multivitamins. One-third of supplement users (8% of US adults) specifically consumes vitamin C supplements daily. Vitamin C is the most commonly supplemented micronutrient in the US. The average vitamin C intake in the form of supplements is about 60 mg; however 6-10% of supplement users consume more than 100 mg of vitamin C daily. There is little evidence that these levels are harmful. Most of the vitamin C is extracted in urine. One study showed that while the body absorbed 70% of the vitamin C, the vast majority of that was not metabolized. Thus a 500 mg dose resulted in the body only using 110 mg. (See: Levine M, Conry-Catilena C, Wang Y, et al. Vitamin C pharmacokinetics in healthy volunteers: evidence for a recommended dietary allowance. Proc Natl Acad Sci 1996; 93:3704-3709).
Kidney Stones and Vitamin C
A majority of kidney stones (technical name: renal calculi) are composed of calcium oxalate. Development of kidney stones is related to a number of factors including lack of inhibitors of crystal formation in urine, changes in urinary pH, decreased urine volume and presence of bacteria. Risk factors to develop this condition include excessive intake of meat protein, oxalate and sodium, insufficient in take of fiber and fluids and higher ambient temperature and exposure to sunlight.
Epidemiological data do not support an association between intake of vitamin C supplements and kidney stones. (See: Curhan GC, Willet WC, and RIMM EB et al. A prospective study of the intake of vitamin C and B6 and the risk of kidney stones in men. Journal of Urology 1996; 155:1847-1851.)
Cardiovascular Death and Vitamin C
Data from the National Health & Nutrition Examination Survey (NHANES) Epidemiological Follow-up Study showed that deaths from cardiovascular disease was inversely related to regular use of vitamin C supplements in males. Conversely, in postmenopausal women (n=34,486) supplemental vitamin C (>1000 mg/day) was not significantly associated with a decrease risk of death due to cardiovascular disease. All-cause carrier deaths were inversely related to regular use of vitamin C supplements in males. (See: Enstrom JE, Kanim LE, Klein MA. Vitamin C intake and mortality among a sample of the United States population. Epidemiology 1992; 3:194-202.)
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By Allan and Harold Rubin, MS, ABD, CRC, Guest Lecturer
updated November 23, 2013