Certain foods have long been known to have positive effects on the body – ancient Egpytians used to eat liver in order to treat night blindness – which now we know is associated with vitamin A, a vitamin found in high amounts in liver. Perhaps one of the more famous cases of vitamin use was in sailors during the 18th century, when scottish surgeon jameslind figured out that citrus fruit prevented scurvy amongst the crewsmen. It wasn’t until the late 18th and early 19th century when people actually began to figure out and separate vitamins as a separate entity by running deprivation studies in rats. By the 20th century, many vitamins were isolated and scientists were able to recognize some of the specific roles that each played in human health.
Who takes vitamins? Well, a lot of people. Almost 60% of Canadians take vitamin supplements, and are spending close to a BILLION dollars on them per year. So this is clearly a very popular industry. But what are vitamins and minerals, why do we need them? $7.84 billion on alternative medicine products
Both Vitamins and minerals are required for normal body functions. We can’t make either of these ourselves, so we have to get them from our diet. But what’s the difference between them? Minerals like calcium, sodium, and iron are just a single particle, or just one lego piece. Meanwhile, vitamins, like vitamins A, B, C, D… etc are a complex group of molecules, a whole lego creation.
So then, what are we referring to when we say dietary supplements? The best definition I found comes from the US Dietary Supplement Health and Education Act, which states that a nutritional supplement is defined as a product intended to supplement the diet, containing one or more dietary ingredients (including vitamins, minerals, herbs, amino acids, or other botanicals), and to be taken by mouth as a pill, capsule, tablet, or liquid
Do you think of pills or foods? If you think of pills, you may be missing the point – healthy foods that contain many of the vitamins we need contain much more than any one pill could – combinations of these vitamins and minerals, not to mention fibre, antioxidants and other nutrients. Vitamins support health but aren’t a cure all, and supplements don’t offer many of the other benefits that come with vitamin-rich foods.
So we talked about vitamin D and its role in bone health, but vitamin D also plays a role in muscle strength. A deficiency of vitamin D increases muscle weakness, and may increase the risk of falls. Your muscles are weaker, and can’t respond as well to an imbalance, perhaps causing you to fall. This is a risk factor for those with osteoporosis or elderly populations, where the risk of breaking bones is high and can be very serious. A study showed that increasing vitamin D intake decreases your risk of falling, especially when you combine vitamin D and calcium together. However, this doesn’t necessarily translate into decreased risk of actually breaking bones – the results from many studies aren’t as clear on that point. from two recent studies and 1 review, the benefit isn’t clear – with one study even suggesting that there was no decrease in the risk of fractures, and an increased risk of kidney stones, especially if vitamin D supplements were combined with calcium.
Many people living in northern or southern areas are more prone to certain cancers and have an increased risk of dying from these cancers. Several studies have looked at the level of vitamin D in blood to figure out if vitamin D and cancers are related. Many studies have found a good relationship between higher levels of vitamin D in your blood and lower rates of certain cancers – specifically, colorectal, breast, and prostate cancers, and non-Hodgkin’s lymphoma. Another large study found that postmenopausal women who increased their vitamin D intake significantly decreased their risk of cancers. The theory behind this finding is that vitamin D can act like a self-destruct button in cells that are beginning to become cancerous – killing the cell before it has the chance to replicate and spread. However, these results are still unclear. Several studies have shown a good relationship between a low level of vitamin D in the blood and the development of cancer, but not a good correlation between vitamin D supplementation and decreased cancer or survival rates. For now research indicates that tumors with a receptor for vitamin D have a better prognosis, but it cannot say definitively that supplementing with vitamin D will prevent cancer.
So this is a pretty common picture in Vancouver for about 8 months of the year… rain. And grey, and early nights.
Vitamin d and flu. Vitamin e and skin . Summary cold and flu – vitamin c and d. review slide. Printout! Checkmarks and x’ss
Vitamin C is one of the more “famous” vitamins, with plenty of health claims form curing the common cold to preventing cancer. It’s found in a variety of foods, mainly fruits and vegetables such as citrus, peppers, broccoli and potatoes. A deficiency of vitamin C is also a famous disease: Scurvy. Many of us know scurvy as the disease that affected sailors during long voyages. Vitamin c is required to make new body tissue, so a lack of it causes tissue that is constantly regenerating to degrade – showing up in the gums and skin. This is cured readily by vitamin C consumption and takes about 5 days. Vitamin C has been linked to the common cold, too, but clinical studies have actually shown that while it may reduce the severity of symptoms, it doesn’t prevent the cold and the effect that it does have is barely noticeable. Too much vitamin C is also not a good thing, and because it is a very common vitamin supplement, upper limits have had to be set. At high intakes, vitamin c can cause gastrointestinal distress and diarrhea. In those prone to kidney disease, excess vitamin C can cause gout and kidney stones. Also, Vitamin C is one of the more notable antioxidants. But with all the hype around this word, what exactly does that mean? Antioxidants defend the body against damaging molecules in the body. But too much of a good thing isn’t great either – excess antioxidant consumption is damaging too. Too much vitamin c consumption actually ends up creating the damaging molecules that it was initially taken to avoid. Reaching your vitamin C requirement for the day is easy – your requirement can be met with one potato or with ½ cup of red bell pepper. Women’s requirements can be met with a kiwi alone.
Vitamin D is found in few foods, but is special in that you can make it yourself by exposure to sunlight. It is found in fish and vitamin-D fortified foods like milk, orange juice, cereals and yogurt. Many people also reach their vitamin D requirements by taking supplements, especially here in Canada where we sometimes don’t see the most sun. Vitamin D works together with calcium in keeping your bones strong and healthy. Vitamin D helps calcium absorption from your gut and helps keep the levels of calcium in your body at the right amounts. Together vitamin D and calcium are important for bone growth, and a deficiency in vitamin D may lead to a disorder called Rickets in children. Rickets is a disorder where the bones become brittle, weak and misshapen – the bowed shape seen in this photo. Vitamin D is also important for immune function and cell growth. So how much vitamin D do we need every day? It’s hard to estimate how much we get from sunlight – it depends on the season, cloud cover, how far north or south we are… but people aged 19-50 years need 600 IUs per day, while those over 70 need 800 IUs per day. Vitamin D obtained from sun exposure, food, and supplements is biologically inert and must undergo two hydroxylations in the body for activation. The first occurs in the liver and converts vitamin D to 25-hydroxyvitamin D [25(OH)D], also known as calcidiol. The second occurs primarily in the kidney and forms the physiologically active 1,25-dihydroxyvitamin D [1,25(OH)2D], also known as calcitriol.In addition, 4% of Canadians aged 6 to 79, or just over 1.1 million people, were considered vitamin D-deficient.
Vitamin a, and its precursor, are found in many animal-derived foods and leafy green and colourful veggies. You may be more familiar with linking vitamin a, or in truth, beta –carotene, with carrots and eyesight. Vitamin A is also known as retinal, an important component of cells in your eyes that aids in absorbing light. It also aids in proper formation of the cornea and conjunctiva, the parts of your eye that you can see and that are exposed to air. Vitamin A is also one of the more famous widespread supplements, and is the special ingredient in “golden rice” – a product that is responsible for preventing millions of cases of blindness worldwide. Children who consume a diet low in vitamin A, so a diet of mainly starchy grains, like rice, don’t get very much vitamin A. This caused millions of cases of blindness in young children worldwide, until the development of this golden rice. So clearly vitamin A is an extremely important component of our diets. But too much of a good thing isn’t good either – vitamin A is one of the few vitamins that we really see toxicity with Important for: Vision, immune function, blood cell productionGolden Rice!Toxicity: liver damage, dry/peeling skin (especially near mouth), osteoporosis
Calcium is the most abundant mineral in your body. It makes up much of your teeth and bones, helps with blood clotting after you’ve been cut, helps your nerves send messages around your body, and helps your heart and cardiovascular system work properly. You’d think that we’d need to eat a lot of calcium every day to keep all these functions going, but your body is very good at regulating how much calcium it absorbs and keeps. In fact, with changes in dietary calcium – that is, calcium from foods like milk, salmon, and green leafy veggies – don’t change the amount of calcium you have floating around your body. Your bones act as a kind of storage system for calcium: when you’re low on calcium, special cells break down some of the calcium stored here, and when your body has too much calcium, cells will put it back. This may change with age, however. When you’re growing, for example when you’re a child or an adolescent, you are adding a lot of calcium to your bones. As we get older, especially once women have passed menopause, the amount of calcium extracted from bones may be more than is put back. This may lead to a condition called Osteoporosis, or when your bones become weaker and may break more easily. But I want to come back to the idea that your body is very good at regulating how much calcium it keeps around. A recent study - you may have heard about it, it was featured on CBC – found that calcium supplements, and not calcium from the diet, caused an increase in heart attacks. This is an important distinction, and research shows that Dietary calcium is more slowly absorbed whereas these concentrated calcium supplements may potentially contribute cardiovascular problems (calcification of blood vessels).
Iron is one of the most well-known minerals present in your body. Many of you may be familiar with one of its more famous roles, which is the transport of oxygen all around your body. This helps your body A deficiency in iron may cause you to become pale and tired, as well as increasing the amount of times you get sick. It can be caused by blood loss, for example from menstruation, severe trauma, or surgery, or it may be caused by an iron poor diet, not absorbing enough dietary iron, pregnancy, or the rapid growth that takes place during infancy, early childhood, and adolescence. However, too much iron isn’t good either: iron toxicity may cause constipation or diarrhoea, nausea, vomiting or even death. Women who are of reproductive age, vegetarians, children or pregnant women may need more iron that other groups, but not always. You should be sure to talk to your doctor before taking an iron supplement. Heme iron vs non-heme iron: your body absorbs heme iron (animal-based) much more easily than non-heme (plant-based)
Observational studies have shown that a diet rich in fruits and vegetables is associated with a decreased incidence of certain cancers. It was believed that it was the antioxidants in these foods that caused this decrease – the vitamins a, c and e. There have been few randomized controlled trials that have looked directly at the interaction between these vitamin supplements and cancer rates, and most of the research comes from observational studies. Originally these observational studies showed promising results between antioxidant supplements and decreased incidence of certain cancers, but the randomized controlled trials, or the gold standards, have shown different results. These studies have shown no evidence that antioxidants decrease cancer rates, and in fact, beta carotene and vitamin E have shown t cause an increased rate of mortality and cancer. Specifically, two large studies showed that beta-carotene increases the relative risk of lung cancer. The theory behind this is that when high levels of antioxidants are consumed, they begin to act as a pro-oxidant, doing the exact role they were taken to prevent. They may also prevent normal routes of cell death, so if cancer cells are told to self-destruct, this pathway may be interfered with.
As I mentioned before, calcium supplements have recently been linked to an increased risk of cardiovascular disease. These are pretty recent findings, and there is still some conflicting evidence – one study found that calcium supplements were associated with a decreased mortality risk, so a decrease in death regardless of cause. However, a large review or 9 randomized controlled trials, which again you’ll recognize as the gold standard, found that calcium supplementation was associated with an increased risk of heart attack. The idea behind the finding is this: when you begin to experience cardiovascular disease, your blood vessels may stiffen and plaque may form, causing a condition called atherosclerosis if its in your coronary arteries, or arteriosclerosis if it happens elsewhere in your body. These plaques may become calcified and harden further. When this calcification happens, you’re at an increased risk of these plaques breaking free and clogging up a smaller artery downstream – perhaps causing a heart attack or stroke.
Apart from skin cancer, prostate cancer is the most common cancer in American men. The recommended daily allowance (RDA) for vitamin E, for instance, is 22 iu, but your average vitamin E pill contains 18 times that. Similarly, a diet rich in fruit and vegetables provides around 200 mg vitamin C per day, yet supplement doses of 1000mg (1g) are routinely taken. A meta-analysis of trials published in 2008 found that dietary vitamin C (from food such as oranges and red peppers) can offer protection against heart disease, and even reduce the risk of breast cancer in women with a family history of the disease. But the same trials found these reductions in risk did not exist in those taking vitamin C supplements, reported the European Journal of Cardiovascular Prevention and Rehabilitation. (And while many people think that if you take too much vitamin C any excess is simply excreted by the body, in high doses, some of the excess will still be absorbed.) Vitamin E has 8 forms in the body – but supplements only have 1. if you ingest very high levels of only one type, others are “kicked out” to make room In most such studies, persons who ate a relatively large quantity of vegetables, fruits, and grains were found to have a profoundly lower risk of death, particularly from cardiovascular disease and cancerReference: EA Klein, IM Thompson, CM Tangen, JJ Crowley, MS Lucia, PJ Goodman, L Minasian, LG Ford, HL Parnes, JM Gaziano, DD Karp, MM Lieber, PJ Walther, L Klotz, JK Parsons, JL Chin, A Darke, SM Lippman, GE Goodman, FL Meyskens, and LH Baker. Vitamin E and the Risk of Prostate Cancer: Results of The Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA. October 12, 2011. 306(14) 1549-1556.
Dietary Supplements:Vitamins and Minerals
Overview• History and discovery of Vitamins and Minerals• What are vitamins and minerals?• Multivitamins• Focus: Disease and injury prevention• General benefits and risks
Who takes dietary supplements?• 57% of Canadians have purchased vitamins• Sales of vitamins and dietary supplements are estimated to be worth $865 million
Vitamin vs. Mineral(e.g. Vitamin C) (e.g. Calcium) • Can’t make them ourselves • Need for normal body function • Get from our diet
What is a supplement?• “A product intended to supplement the diet, containing one or more dietary ingredients (including vitamins, minerals, herbs, amino acids, or other botanicals) and to be taken by mouth as a pill, capsule, tablet or liquid.”
Vitamins and Nutrition• What comes to mind when you think of vitamins?
Multivitamins • Combination of 3+ vitamins and/or minerals • Contain less than the tolerable upper limit for vitamins or minerals“We cannot recommend the use of vitamin and mineral supplements as apreventive measure, at least not in a well nourished population…thosesupplements do not replace or add to the benefits of eating fruits andvegetables and may cause unwanted health consequences.” -Bjelakovic and Gluud, Arch Intern Med. 2011
Focus: Disease and Injury Prevention• Vitamin D• Antioxidants: Vitamin A, C, and E• Calcium
Does Vitamin D help prevent injury and disease?• Fractures• Falls• Cancers• Depression
Vitamin D and Fractures/Falls• Vitamin D deficiency increases muscle weakness• Increased vitamin D intake may decrease risk of falls ▫ Greatest impact seen when vitamin D combined with Calcium• Results not as clear for fracture risk: ▫ Study 1: decreases fractures ✔ ▫ Review 1: No decrease ✗ ▫ Study 2: No decrease ✗ BUT increased risk of kidney stones 1. Chapuyet al. N Engl J Med. 1992. 2. Bischoff-Ferrari et al. AJCN. 2006. 3. Grant et al. Lancet. 2005.
Vitamin D and Cancer• Blood levels of vitamin D may reflect your chances of developing certain cancers• Low levels of vitamin D in your blood may correlate to higher rates of: ▫ Colorectal cancer ▫ Breast cancer ▫ Prostate cancer ▫ Non-Hodgkin’s Lymphoma• However, supplementing with vitamin D hasn’t shown a decrease in your risk of developing these cancers 1. Holick, MF. N Engl J Med. 2007. 2. Martinez et al. JNCI. 2012.
Vitamin D and Depression • Seasonal Affective Disorder (S.A.D.) • Vitamin D deficiency linked to increased rates of depression • Treatment: UV lamp ▫ Some evidence that vitamin D supplement may help ▫ Still need more! Bertone-Johnson. Nutr Review. 2009.
Does Vitamin D help prevent injury and disease?• Fractures ✗• Falls ✔• Cancers ?• Depression ?
Comment on the common cold and flu:What works?• Vitamin C: ▫ May reduce severity of symptoms slightly ▫ Doesn’t prevent the common cold• Vitamin D: ▫ Good evidence that vitamin D deficiency associated with flu 1. Li-Ng et al. Epidemiol Infect. 2009. 2. Urashimaet al. AJCN. 2010.
What are the risks? • Toxicity ▫ Vitamins have an upper limit! • False sense of security ▫ Why bother with the carrots? • Interfere with the absorption of other nutrients ▫ Vitamin K and Vitamin E or A ▫ Vitamin C and Copper ▫ Zinc and iron • Misleading claims ▫ Cure cancer? • Expensive!
When are supplements needed?• Can prevent or correct deficiencies ▫ BUT Canadians rarely suffer from nutrient deficiency• Specific Groups: ▫ Women may require an iron supplement ▫ Newborns (Vitamin K) ▫ Pregnancy (folic acid) ▫ Limiting dietary practices (e.g. veganism) ▫ Illnesses (gastritis and B12)• Physicians may prescribe a dose: Vitamins are drugs, too!
Summary• Vitamins and minerals are in a wide variety of foods ▫ What your body does with them differs- food vs. supplement• More quality research must be done to prove claims“With the possible exceptions of Vitamin D and omega-3 fatty acids there is no data to support the widespread use of dietary supplements in Westernized populations; indeed, many of these supplements may be harmful.” Supplements are drugs, and should be treated as such – discuss them with your physician before taking them! Marik and Flemmer. JPEN. 2012.
Common Vitamins• Antioxidants ▫ Vitamin C ▫ Vitamin E• B Vitamins• Vitamin D• Vitamin A (beta-carotene)
Vitamin C• Antioxidant• Deficiency: Scurvy• Does Vitamin C help cure the common cold? * The Daily requirement for almost everyone can be met• Toxicity: Diarrhea, kidney with ½ cup red bell pepper or stones/gout in those with one potato. kidney disease *Women’s requirements can be met with 1 kiwi!
Vitamin D• Can make it yourself!• Helps calcium absorption and maintenance• Immune system and cell growth• Needed for bone growth ▫ Deficiency = Rickets in children• Found in oily fish and vitamin D-fortified foods (milk, orange juice, yogurt) ▫ Sun exposure ▫ Supplements
Beta-Carotene (Vitamin A)• Important for: Vision, immune function, blood cell production ▫ Deficiency = Blindness in children, night blindness in adults ▫ Golden Rice!• Found in leafy green and colourful veggies and many animal- derived foods• Toxicity: liver damage, dry/peeling skin (especially near mouth), osteoporosis
B Vitamins• B1 (Thiamine), B2 (Riboflavin), B3 (Niacin), B5 (Pantothenic Acid), B6, B7 (Biotin), B9 (Folic Acid), B12• Found in many unprocessed foods• Functions: Maintain healthy skin, hair, muscle tone, immune function, nervous system, and promote blood cell production ▫ 2008 Study: Reduces the risk of pancreatic cancer Reduction seen with B6, B12 in foods – NOT supplements Schernhammeret al. Cancer Research. 2007.
Calcium• Found in : dairy, green leafy veggies, fish • Deficiency = osteoporosis • "It is now becoming clear that taking this micronutrient in one or two daily boluses is not natural, in that it does not reproduce the same metabolic effects as calcium in food." –Prof. Ian Reid
Iron • Found in: meat, eggs, dairy, some cereals • 2 types: heme iron and non- heme iron • Functions: Transports oxygen around the body ▫ Deficiency= anemia Paleness, feeling tired, poor immune function • Toxicity: Constipation, diarrhea, nausea, vomiting
What about Antioxidants – Vitamin A, C and Vitamin E?
Vitamin A,C, E and Cancer• Antioxidants: a way to prevent cancer?• Not the case, we think: ▫ Review of 78 studies found: No evidence that antioxidants prevent cancer Significant evidence that vitamin E, A and beta- carotene actually increase risk of death ▫ Conclusion: “Antioxidant supplements need to be considered as medicinal products and should undergo sufficient evaluation before marketing.” 1. Bjelakovicet al. Cochrane Database. 2012 2. Martinez et al. JNCI. 2012.
Calcium and Cardiovascular Disease• Some conflicting results: ▫ Study 1: calcium supplements associated with decreased mortality risk ▫ Review of 9 randomized controlled trials: Calcium associated with increased risk of heart attack
Supplements and Cancer• Some show positive results: ▫ Vitamin D associated with decreased risk (especially digestive cancers)• Antioxidants: all they’re cracked up to be? ▫ You can have too much of a good thing! ▫ Vitamin E: increased risk of prostate cancer (dose dependent) ▫ Vitamin A (beta-carotene) – lung cancer