Some answers to common questions about vitamins, how much water to drink in a day, and whether sunblock and sunscreen are the same.

A friend recently asked me whether the higher-end brands of vitamins are better than the cheaper generic or store brands, and if so why? The short answer is no – the more expensive brands are not necessarily better than the less expensive ones - at least according to the experts at the Mayo Clinic. In fact, the folks at the Mayo suggest that it’s not price you should be checking, but labels. The labels for multivitamins, for example, should indicate that the multivitamin levels contain 100% of the Daily Value (DV) of most essential nutrients. Interestingly, they point out that large doses of vitamins and nutrients, which is considered more than the recommended DV, and pills that contain extras like herbs, amino acid, and enzymes should be avoided because they may pose a health risk, particularly if you’re taking prescription medications.

Another common question about vitamins is whether or not iron it’s a good idea to take a multivitamin with iron. Again, according to the the Mayo Clinic, for premenopausal women it’s not a bad idea, as it can help to replace iron lost during menstruation. For postmenopausal women, eating a healthy, well balanced diet should provide enough iron.

I know this gets said a lot but it’s true  - eating a well balanced diet is the best source of nutrients for your body. But, if you have health conditions, lifestyle habits or medications that affect your ability to eat or absorb the proper amounts of essential nutrients, multivitamins are recommended. Also, aging can negatively impact your ability to absorb vitamins such as B-12, a vitamin that may reduce the risk for anemia, and vitamin D which we all know helps to maintain bone strength.  So for people over 60 multivitamins may also be a good idea. But is important to consult your doctor first – especially if you are taking medications for certain health conditions – because some nutrients can interfere with certain medications. For example, vitamin K can negatively impact warfarin – a blood thinner used to prevent stroke.

And what extra supplements? Calcium is a good example – should you take additional calcium? Well, most multivitamins don’t contain enough calcium for women – especially women going through menopause or who are postmenopausal, which is when bone loss accelerates. To quote the Mayo Clinic yet again, after the age of 50, women should be getting 1,200 to 1,500 milligrams of calcium daily. And – calcium is best absorbed when taken several times a day in amounts of 500 milligrams or less.

Folic acid is another ‘additional supplement’. If you are a premenopausal woman who is considering having children, it is worth consulting your physician about taking folic acid. There is now good evidence to show that it can reduce the risk of spinal cord defects. In fact, folic acid supplementation of white flour and cereal products in Canada was found to have reduced neural-tube defects by 46%, and reduced spina bifida by 53%, according to a recent study by Philippe De Wals, Ph.D., of Laval University, which was reported in the July 12 2007 issue of the New England Journal of Medicine.

Now what about washing down those vitamins – how much water should we be drinking a day? Well apparently – and here’s a surprise  - it varies! And, to stay properly hydrated you don’t necessarily have to drink water.  Women who are ‘properly hydrated’ drink about 2.7 liters or 91 fluid ounces of water a day. Food typically contains about 20% of your daily fluid intake, so drinking 2.2 liters or 74 fluid ounces – or about 9 cups of water – or non-alcoholic beverages a day– should do the trick under normal conditions. You can tell if you’re properly hydrated by the color of your urine – if it’s clear or slightly yellow – you’re in good shape. Similarly, some signs of dehydration you may recognize include headaches, dry mouth, light-headedness, little to no urination, and constipation.

Factors that can increase your need for fluids include dry indoor air, high altitudes – air travel comes to mind here, increased physical activity, and illness – particularly fever, vomiting and diarrhea. (If you have vomiting and diarrhea read my column on the BRAT diet. If you have persistent vomiting and diarrhea – see your doctor as soon as possible). Hot and humid weather can also increase your need for fluids –including water.

And speaking of hot and humid weather – let’s change the subject completely– what about sunblocks and sunscreens – are they the same? According to the experts at Harvard Health Publications, a publishing division of Harvard Medical School, no – the two types of products are not the same. Sunblock does just that – blocks the sun – by reflecting the sun’s rays. Sunscreen absorbs rather than reflects ultraviolet radiation.

Sunblocks contain zinc oxide and titanium dioxide and are very effective at protecting against both ultraviolet A (UVA) and ultraviolet B (UVB) light. UVA and UVB are the two types of rays that cause sunburn and skin cancer. Having said that, however, UVB is a good source of vitamin D, so 10 minutes with the sun on your hands and face, once or twice a day, has health benefits. FYI- in addition to providing bone strength vitamin D is important for a healthy immune system.

Okay, back to sunscreens. Sunscreen contains benzophenones, which provide protection against UVA, and cinnamates and salicylates, which are usually listed on the packaging as oxybenzone, octyl salicylate, or octyl methoxycinnamate – and these protect against UVB. The problem with sunscreens is that they wear off – the ingredients breakdown after several hours of sun exposure, and must be reapplied.

BUT two new sunscreens now commercially available offer longer-lasting protection against UVA and UVB – they are Anthelios SX and Helioplex. Anthelios SX, approved by the Federal Food and Drug Administration in the USA in 2006, reportedly maintains 80% of the UVA protection and 90% of the UVB protection for up to five hours after being applied.

If you have a comment or question contact: claire@knowitallhealth.com

Reviewed March 4th 2008