Breaking News
February 21, 2019 - Mayo clinic researchers discuss local case studies of leprosy
February 21, 2019 - Scientists demonstrate key role of salt in allergic immune reactions
February 21, 2019 - Experts propose revising the criteria for diagnosis of Parkinson’s disease
February 21, 2019 - The med student and the machine
February 21, 2019 - Hey, Hey! Ho, Ho! Is Striking For School Nurses The Way To Go?
February 21, 2019 - Latest research encourages children to move out and learn through physical activity
February 21, 2019 - Proper oral hygiene and regular visits to dentist can promote heart health
February 21, 2019 - New, versatile technique for remote control of transplanted cells in Parkinson’s
February 21, 2019 - Why melanoma tumors in the brain may be worse?
February 21, 2019 - New project aims to improve lung disease care in Appalachia
February 21, 2019 - Drug increases melanin production in some people with albinism
February 21, 2019 - Over 1 in 3 adults miss the mark on protein, finds study
February 21, 2019 - CymaBay Therapeutics Announces Seladelpar Granted Breakthrough Therapy Designation by the FDA for the Treatment of Primary Biliary Cholangitis
February 21, 2019 - A correlation between obesity and income has only developed in the past 30 years
February 21, 2019 - Baby, then work: An effort to help resident-parents in emergency medicine
February 21, 2019 - Heavy cigarette smoking could damage vision, say researchers
February 21, 2019 - Some drug combinations may be more effective than others for schizophrenic patients
February 21, 2019 - Combination of common antibiotics can eliminate multi-drug resistant E. coli
February 21, 2019 - New computational tool searches for factors that cause specific diseases
February 21, 2019 - New method to assess effectiveness of psychotherapies for social anxiety disorder
February 21, 2019 - New technology measures hormones that influence reproductive health efficiently
February 21, 2019 - Bat influenza viruses could potentially attack the cells of humans and livestock
February 21, 2019 - Immunotherapeutic antibody therapy to kill cancer has now progressed to patient testing
February 21, 2019 - Johns Hopkins scientists find new compound that may prevent reperfusion injury
February 21, 2019 - Researchers develop new way to deliver treatment for cartilage regeneration
February 21, 2019 - Study sheds new light on left ventricular dysfunction in ischemic heart disease
February 21, 2019 - New technique could expedite cancer diagnosis, lead to better patient outcomes
February 21, 2019 - New map of infant brain may aid early diagnosis of autism
February 21, 2019 - Human consciousness depends on the brain’s ability to maintain dynamics of neural activity
February 21, 2019 - Harmony Biosciences Announces File Acceptance Of Its New Drug Application For Pitolisant
February 21, 2019 - Medications could fill treatment gap for adolescents with obesity
February 21, 2019 - New antibiotics are desperately needed: Machine learning could help | News Center
February 21, 2019 - Researchers develop new computer game for dementia carers
February 21, 2019 - University of Dundee partners with Takeda to develop new treatments for tau pathology
February 21, 2019 - Influenza vaccine may be less effective in elderly patients, finds study
February 21, 2019 - Researchers explain why T cells lose their protective ability in inflamed tissues
February 21, 2019 - New optimization method rapidly analyzes nanomedicines for cancer treatment
February 21, 2019 - Viruses in the intestinal tracts can lead to islet autoimmunity and Type 1 diabetes
February 21, 2019 - Link between dietary fatty acid intake and hypertension found to be influenced by diabetes status
February 21, 2019 - FDA Approves Esperoct (turoctocog alfa pegol, N8-GP) for Hemophilia A
February 21, 2019 - ‘Boy erased’—why conversion therapies and ex-gay ministries should be outlawed
February 21, 2019 - Titia de Lange to give annual McCormick Lecture on March 8 | News Center
February 21, 2019 - Study reveals how helper T cells support memory cells to function optimally
February 21, 2019 - Autistic children with co-occurring ADHD have greater adaptive behavior impairments
February 21, 2019 - Elevated levels of key cellular process implicated in intestinal inflammation and IBD
February 20, 2019 - Over Half of Hip Replacements Expected to Last 25 Years
February 20, 2019 - Microscopic eye movements affect how we see contrast
February 20, 2019 - Computer vs. patient: Fighting for residents’ attention | News Center
February 20, 2019 - New “Smart Drug” Shows Promise for Metastatic Triple-Negative Breast Cancer
February 20, 2019 - Researchers develop large-scale window material for high-efficiency PM2.5 capture
February 20, 2019 - Widespread confusion among consumers on food date labels lead to unnecessary discards
February 20, 2019 - Researchers unlock plant’s secret of producing specialized metabolites
February 20, 2019 - Newly released national framework identifies obstacles to improving EMS systems
February 20, 2019 - Exercise can shift human body clock depending on time when people work out
February 20, 2019 - Female adolescent blood donors more likely to have iron deficiency and related anemia
February 20, 2019 - Rubicon level linked to inhibition of autophagic process
February 20, 2019 - Researchers find potential therapeutic strategy to treat Alzheimer’s
February 20, 2019 - New forms of older anti-cancer agent appear to enhance immune response to fight melanoma
February 20, 2019 - Health Tip: Eat Less Saturated Fat
February 20, 2019 - Sleeping in contact lenses puts you at risk of dangerous infection
February 20, 2019 - “We should study that!”: How a nurse-scientist found her passion
February 20, 2019 - Cervical microbiome may influence HPV infection more than previously thought
February 20, 2019 - Sausage mislabeling in Canada is down, new study finds
February 20, 2019 - Study shows blood pressure benefits of morning exercise for older overweight/obese adults
February 20, 2019 - New screening method could catch organ rejection much earlier without a biopsy needle
February 20, 2019 - Study may have important implications for refining parenting during child’s adolescence
February 20, 2019 - Study sheds new light on how antibiotic resistance genes are transferred between bacteria
February 20, 2019 - Chronic Wasting Disease may soon spread to humans, warns CDC
February 20, 2019 - Scientists identify new genetic causes linked to abnormal pregnancies and miscarriages
February 20, 2019 - Using LyoSpeed technology to avoid residual solvent when drying HPLC fractions
February 20, 2019 - New AI can identify, predict development of different combinations of cancer symptoms
February 20, 2019 - Scientists join forces to identify a new approach to fight African sleeping sickness
February 20, 2019 - New screening tool more likely to identify sexual and labor exploitation of youth
February 20, 2019 - Newly licensed nurses work for long hours, also have a second paid job
February 20, 2019 - Physicists identify simple mechanism used by deadly bacteria to fend off antibiotics
February 20, 2019 - FDA Grants Priority Review to Genentech’s Personalized Medicine Entrectinib
February 20, 2019 - Exposure to chemicals before and after birth is associated with a decrease in lung function
February 20, 2019 - Neuroscientists reveal that simple brain region can guide complex feats of mental activity
February 20, 2019 - Study finds new link between food allergies and multiple sclerosis
February 20, 2019 - First gene therapy operation for macular degeneration is a success
Older Americans are hooked on vitamins despite scarce evidence they work

Older Americans are hooked on vitamins despite scarce evidence they work

image_pdfDownload PDFimage_print

When she was a young physician, Dr. Martha Gulati noticed that many of her mentors were prescribing vitamin E and folic acid to patients. Preliminary studies in the early 1990s had linked both supplements to a lower risk of heart disease.

She urged her father to pop the pills as well: “Dad, you should be on these vitamins, because every cardiologist is taking them or putting their patients on [them],” recalled Gulati, now chief of cardiology for the University of Arizona College of Medicine-Phoenix.

But just a few years later, she found herself reversing course, after rigorous clinical trials found neither vitamin E nor folic acid supplements did anything to protect the heart. Even worse, studies linked high-dose vitamin E to a higher risk of heart failure, prostate cancer and death from any cause.

“‘You might want to stop taking [these],'” Gulati told her father.

More than half of Americans take vitamin supplements, including 68 percent of those age 65 and older, according to a 2013 Gallup poll. Among older adults, 29 percent take four or more supplements of any kind, according to a Journal of Nutrition study published in 2017.

Often, preliminary studies fuel irrational exuberance about a promising dietary supplement, leading millions of people to buy in to the trend. Many never stop. They continue even though more rigorous studies — which can take many years to complete — almost never find that vitamins prevent disease, and in some cases cause harm.

“The enthusiasm does tend to outpace the evidence,” said Dr. JoAnn Manson, chief of preventive medicine at Boston’s Brigham and Women’s Hospital.

There’s no conclusive evidence that dietary supplements prevent chronic disease in the average American, Manson said. And while a handful of vitamin and mineral studies have had positive results, those findings haven’t been strong enough to recommend supplements to the general U.S. public, she said.

The National Institutes of Health has spent more than $2.4 billion since 1999 studying vitamins and minerals. Yet for “all the research we’ve done, we don’t have much to show for it,” said Dr. Barnett Kramer, director of cancer prevention at the National Cancer Institute.

In Search Of The Magic Bullet

A big part of the problem, Kramer said, could be that much nutrition research has been based on faulty assumptions, including the notion that people need more vitamins and minerals than a typical diet provides; that megadoses are always safe; and that scientists can boil down the benefits of vegetables like broccoli into a daily pill.

Vitamin-rich foods can cure diseases related to vitamin deficiency. Oranges and limes were famously shown to prevent scurvy in vitamin-deprived 18th-century sailors. And research has long shown that populations that eat a lot of fruits and vegetables tend to be healthier than others.

But when researchers tried to deliver the key ingredients of a healthy diet in a capsule, Kramer said, those efforts nearly always failed.

It’s possible that the chemicals in the fruits and vegetables on your plate work together in ways that scientists don’t fully understand — and which can’t be replicated in a tablet, said Marjorie McCullough, strategic director of nutritional epidemiology for the American Cancer Society.

More important, perhaps, is that most Americans get plenty of the essentials, anyway. Although the Western diet has a lot of problems — too much sodium, sugar, saturated fat and calories, in general — it’s not short on vitamins, said Alice Lichtenstein, a professor at the Friedman School of Nutrition Science and Policy at Tufts University.

And although there are more than 90,000 dietary supplements from which to choose, federal health agencies and advisers still recommend that Americans meet their nutritional needs with food, especially fruits and vegetables.

Also, American food is highly fortified — with vitamin D in milk, iodine in salt, B vitamins in flour, even calcium in some brands of orange juice.

Without even realizing it, someone who eats a typical lunch or breakfast “is essentially eating a multivitamin,” said journalist Catherine Price, author of “Vitamania: How Vitamins Revolutionized the Way We Think About Food.”

That can make studying vitamins even more complicated, Price said. Researchers may have trouble finding a true control group, with no exposure to supplemental vitamins. If everyone in a study is consuming fortified food, vitamins may appear less effective.

The body naturally regulates the levels of many nutrients, such as vitamin C and many B vitamins, Kramer said, by excreting what it doesn’t need in urine. He added: “It’s hard to avoid getting the full range of vitamins.”

Not all experts agree. Dr. Walter Willett, a professor at the Harvard T.H. Chan School of Public Health, says it’s reasonable to take a daily multivitamin “for insurance.” Willett said that clinical trials underestimate supplements’ true benefits because they aren’t long enough, often lasting five to 10 years. It could take decades to notice a lower rate of cancer or heart disease in vitamin takers, he said.

Vitamin Users Start Out Healthier

For Charlsa Bentley, 67, keeping up with the latest nutrition research can be frustrating. She stopped taking calcium, for example, after studies found it doesn’t protect against bone fractures. Additional studies suggest that calcium supplements increase the risk of kidney stones and heart disease.

“I faithfully chewed those calcium supplements, and then a study said they didn’t do any good at all,” said Bentley, from Austin, Texas. “It’s hard to know what’s effective and what’s not.”

Bentley still takes five supplements a day: a multivitamin to prevent dry eyes, magnesium to prevent cramps while exercising, red yeast rice to prevent diabetes, coenzyme Q10 for overall health and vitamin D based on her doctor’s recommendation.

Like many people who take dietary supplements, Bentley also exercises regularly — playing tennis three to four times a week — and watches what she eats.

People who take vitamins tend to be healthier, wealthier and better educated than those who don’t, Kramer said. They are probably less likely to succumb to heart disease or cancer, whether they take supplements or not. That can skew research results, making vitamin pills seem more effective than they really are.

Faulty Assumptions

Preliminary findings can also lead researchers to the wrong conclusions.

For example, scientists have long observed that people with high levels of an amino acid called homocysteine are more likely to have heart attacks. Because folic acid can lower homocysteine levels, researchers once hoped that folic acid supplements would prevent heart attacks and strokes.

In a series of clinical trials, folic acid pills lowered homocysteine levels but had no overall benefit for heart disease, Lichtenstein said.

Studies of fish oil also may have led researchers astray.

When studies of large populations showed that people who eat lots of seafood had fewer heart attacks, many assumed that the benefits came from the omega-3 fatty acids in fish oil, Lichtenstein said.

Rigorous studies have failed to show that fish oil supplements prevent heart attacks. A clinical trial of fish oil pills and vitamin D, whose results are expected to be released within the year, may provide clearer questions about whether they prevent disease.

But it’s possible the benefits of sardines and salmon have nothing to do with fish oil, Lichtenstein said. People who have fish for dinner may be healthier due to what they don’t eat, such as meatloaf and cheeseburgers.

“Eating fish is probably a good thing, but we haven’t been able to show that taking fish oil [supplements] does anything for you,” said Dr. Steven Nissen, chairman of cardiovascular medicine at the Cleveland Clinic Foundation.

Too Much Of A Good Thing?

Taking megadoses of vitamins and minerals, using amounts that people could never consume through food alone, could be even more problematic.

“There’s something appealing about taking a natural product, even if you’re taking it in a way that is totally unnatural,” Price said.

Early studies, for example, suggested that beta carotene, a substance found in carrots, might help prevent cancer.

In the tiny amounts provided by fruits and vegetables, beta carotene and similar substances appear to protect the body from a process called oxidation, which damages healthy cells, said Dr. Edgar Miller, a professor of medicine at Johns Hopkins School of Medicine.

Experts were shocked when two large, well-designed studies in the 1990s found that beta carotene pills actually increased lung cancer rates. Likewise, a clinical trial published in 2011 found that vitamin E, also an antioxidant, increased the risk of prostate cancer in men by 17 percent. Such studies reminded researchers that oxidation isn’t all bad; it helps kill bacteria and malignant cells, wiping them out before they can grow into tumors, Miller said.

“Vitamins are not inert,” said Dr. Eric Klein, a prostate cancer expert at the Cleveland Clinic who led the vitamin E study. “They are biologically active agents. We have to think of them in the same way as drugs. If you take too high a dose of them, they cause side effects.”

Gulati, the physician in Phoenix, said her early experience with recommending supplements to her father taught her to be more cautious. She said she’s waiting for the results of large studies — such as the trial of fish oil and vitamin D — to guide her advice on vitamins and supplements.

“We should be responsible physicians,” she said, “and wait for the data.”

KHN’s coverage related to aging and improving care of older adults is supported in part by The John A. Hartford Foundation.

Liz Szabo: [email protected], @LizSzabo

Kaiser Health NewsThis article was reprinted from khn.org with permission from the Henry J. Kaiser Family Foundation. Kaiser Health News, an editorially independent news service, is a program of the Kaiser Family Foundation, a nonpartisan health care policy research organization unaffiliated with Kaiser Permanente.

Tagged with:

About author

Related Articles