Tuesday, June 3, 2008

Get rid of your multivitamin and eat real food!


This always happens. I want to blog about something, I take too much time and, all of a sudden, my topic is in the news! This time, the topic is vitamin and mineral supplementation. It’s the cover story in this month’s Nutrition Action and Maclean’s magazine.

I’ve never been a fan of vitamin and mineral supplementation, despite the fact that nutrition experts like Dr. Walter Willett recommend a multivitamin a day for “health insurance”, as do many doctors. Well, it makes me happy that the use of a daily multivitamin is being questioned- finally!

According to Stats Canada, nearly half of Canadian adults have taken a multivitamin in the last month (as did more than one in three kids). The supplement industry is huge and works hard to convince you your diet is deficient.

According to the Centre for Science in the Public Interest, there is very, very little evidence that there is any benefit to taking a multivitamin. However, the evidence that there is harm to taking one is not consistent. A handful of studies have found that people taking a multivitamin have a slightly higher risk of cancer and other “negative human consequences”.

Food is abundant in North America and most of us get more than enough vitamins and minerals in our diet, with no risk of overdosing on them. As a result, if you’re healthy and eat a variety of foods, there’s no need to supplement your diet. In fact, you might be better off!

If you insist on taking a multivitamin, here are some of the nutrients you need to be aware of:

Folic acid: High intakes- 1000 mcg (1mg) or more- of folic acid has recently been linked to increased risk of colon and breast cancer. The daily recommended intake is 400 mcg. Women in their childbearing years should continue to take a multivitamin that contains 400 mcg folic acid daily to reduce the risk of birth defects. For men and post-menopausal women that insist on taking a multivitamin, choose one with less than 400 mcg folic acid. If your multivitamin has 400 mcg folic acid, don’t take it every day.

Selenium: The daily recommended intake of selenium is 55mcg/day. Some studies have shown that more than 200mcg selenium a day may increase the risk of skin cancer and diabetes. Choose a supplement with less than 100mcg.

Vitamin C: The daily recommendation for Vitamin C is 75mg for a woman and 90mg for a man (btw, 1 cup orange juice contains 128mg). 250-500mg saturates the body’s tissues so more than that is excreted. However, high doses of 1000mg or more can cause diarrhea, interfere with iron metabolism and contribute to kidney stones.

Vitamin A: The recommendation is 3000 IU a day. Too much retinol (vitamin A palmitate or acetate) can increase your risk of hip fractures, liver problems and birth defects. If you take a supplement, it shouldn’t contain more than 4000 IU retinol or more than 6000 IU beta-carotene.

Vitamin D: Vitamin D helps with the absorption of calcium and recent research has shown that it can help reduce the risk of cancer and diabetes. The current recommendation is 200IU per day but 400IU for people over the age of 50 and 600 IU for people over the age of 70. However, many experts recommend an intake of 1000IU a day for everyone (including the amount that comes from the sun and from food- fish and added in margarine, milk and cereal). Most multivitamins contain 400IU.

Vitamin E: 33IU/day is recommended daily. Research has shown that more than 400IU of vitamin E increased the risk of death. As a result, aim for less than 100IU a day.

Calcium: The recommendation is 1000mg a day for men and women below the age of 50 and 1200mg/day for women above 50. Men who consume more than 1500mg a day are at greater risk for prostate cancer so your multivitamin should contain less than 200mg.

Sources:

Liebman B, Schardt D, Cohen D et al. Multi Complex: Picking a multivitamin gets tricky. Nutrition Action Health Letter. Centre for Science in the Public Interest, June 2008.
Gulli C. How vitamins can be hazardous to your health. Maclean's, Apr 21 2008.
Nestle M. What to eat. NY: North Point Press. 2006

6 comments:

Anonymous said...

interesting. What do you think about those greens supplements? Not really a vitamins, as they are food but do pack alot of nutrients as a consequence. A typical mix:

NON-GMO1 Soy Lecithin 2,239mg
Organic Hawaiian Spirulina Pacifica 1,356mg
Organic High Pectin Apple Fiber 1,350mg
Barley Grass Powder 650mg
Wheat Grass Powder 350mg
Japanese Chlorella 350mg
Organic Soy Sprouts 350mg
Brown Rice Bran 350mg
Sprouted Barley Malt 350mg
Alfalfa Grass Powder 300mg
Seven Dairy-Free Probiotic Cultures containing:
L. Acidophilus ATCC 4356, L. Casei, L. Plantarum, L. Rhamnosus, Bifidobacterium Bifidum And Longum,Fructo-Oligosaccharides 200mg
Royal Jelly 150mg
Montana Mountain Region Bee Pollen 150mg
Acerola Berry Juice Powder (Malpighia glabra) 115mg
Natural Vitamin E (d-alpha-tocopherol-succinate) 118iu2
Licorice Root Powder (Glycyrrhiza glabra) 60mg
Red Beet Juice Powder 50mg
Dunaliella Salina Algae 40mg
Organic Nova Scotia Dulse (Palmeria plamata) 20mg

Milk Thistle Seed (Silybum marianium) 60mg
Echinacea Root (Echinacea angustifolia) 60mg
Siberian Eleuthero Root (Eleutherococcus senticosus) 60mg
Astragalus Root (Astragalus membranaceus) 60mg
Licorice Root (Glycyrrhiza glabra) 60mg

Organic Ginkgo Biloba Leaf 20mg
Organic Japanese Green Tea Leaf (Camellia sinesis) 20mg
Full Spectrum Grape Skin and Seed(Vitis vinifera) 20mg
Organic Swedish Bilberry (Vaccinum mytillus) 10mg



thanks
~mike

Sybil Hebert, RD said...

Hi Mike,
In Canada, natural health products that contain a Drug Identification Number (DIN), a Natural Product Number (NPN) or a DIN-HM number (for homeopathic medecins)have been assessed by Health Canada for safety, quality and health claims. Check to see if your product contains this 8 digit number.
In the States, dietary supplements and natural health products are not subject to the same mandatory review or quality requirements.
A private company- consumerlab.com- tests product samples and has found that, for example, 1/3 of multivitamins tested had levels of nutrients below the amounts stated on the labels. They also found that only 25% of ginkgo supplements and 40% of St. John's Worts samples had what they were supposed to. They also found that 17% of Korean ginseng was contaminated with pesticides and 6 out of 25 oil supplements didn't have the stated amount of fatty acids or were rancid!
So basically, you can't be sure what's in the supplement that you're taking and that can be a bit scary.
There's really very little research that has been done on the long term effects of herbal supplements so taking a 'greens plus' supplement is a risk.
There was a well-designed echinacea study done in 2005 that found that it did not alleviate common cold symptoms.
Your supplement does contain supplemental vitamin E- 182 IU. The Centre for Science in the Public Interest recommends sticking to less than 100 IU in a supplement due to a link with cancer at high doses (the daily recommendation is 33 IU).
Generally, I wouldn't recommend taking the greens supplement since it's not necessary for good health. You get all you need from food. However, as long as the amounts are small, non-nutrient supplements are unlikely to be harmful. Just don't take it every day and, if you have a doctor and a pharmacist, make sure he or she is aware you're taking it.
Hope this helps!
Sybil

Jme said...

Just eat a balanced diet for crying out loud!

ings said...

Really interesting! Too much Vitamin E leads to death!? Scary...

Kay said...

hi, so do u mean multivitamin should be eaten anyway during pregnancy? my multivitamin has soy lecithin in it, i'm against soy products. Do u think it's a problem eating soy lecithin inside the multi? thanks

Sybil Hebert, RD said...

Hi Kay,

Thanks for your question.
During pregnancy most doctors prescribe a pre-natal vitamin that’s beneficial to both mom and baby. Pregnant women have increased needs for certain vitamins and minerals. For example, iron needs are increased during pregnancy and are difficult to meet by diet alone. Pre-natal vitamins also have vitamin C to help with the absorption of iron. Folic acid is an important component of pre-natal vitamins since it’s required to prevent neural tube defects- pregnant women need 0.4 to 1.0mg folic acid (folacin, folate) a day, more if they have a history of NTDs, have a history of certain illnesses and are taking some medications. Pre-natal vitamins have all the vitamins and minerals you need whereas multivitamin may have less or more of certain vitamin and minerals than necessary. For example, taking in more than the recommended intake of vitamin A, (recommendation is 4000 IU) can increase the risk of birth defects. Always talk to your doctor about supplements taken during pregnancy.
The American Dietetic Association suggests (and I agree) that you not be lured by extra ingredients like lecithin- it offers no proven nutritional benefit. According to Heath Canada and the Center for Science in the Public Interest (CSPI), lecithin is believed to be safe but current research finds no effect on blood cholesterol levels. Lecithin is an emulsifier and natural sources include soybeans and eggs. Lecithin is a common ingredient in many processed food due to its role as an emulsifier.
Hope this helped!