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Important Reasons to Soak Up the Sunshine Vitamin

When is a vitamin not really a vitamin? When it's vitamin D! The "sunshine" vitamin, aptly named because sunlight is a source of it, is actually a hormone. Vitamin D is currently receiving a lot of attention and research regarding its role in various diseases. Because it isn't found in many foods, and people tend to slather on sunscreen (which blocks your body's ability to make vitamin D from the sun) or spend most of the day indoors, many are wondering if their intake of vitamin D is sufficient.

Why Vitamin D Matters

A report by the Institute of Medicine (IOM) indicates that there is strong scientific evidence showing that vitamin D plays an important role in bone health. Vitamin D then helps to deposit these minerals in your skeleton and teeth, making them stronger and healthier. Therefore, vitamin D helps prevent the fractures associated with osteoporosis, the bone deformation of rickets, and the muscle weakness and bone aches and pains of osteomalacia (the softening of bones).

But a deficiency of vitamin D may go beyond bones—it may be related to a variety of health problems. Because it's a hormone, and your body is full of receptors for this hormone, it may play a role in the prevention of other ailments. After analyzing more than 1,000 studies the IOM believes that there is not substantial evidence to support vitamin D's role in other diseases. But preliminary research indicates the importance of meeting one’s basic daily needs for vitamin D is important for overall health and well-being. A lack of vitamin D has been blamed for a plethora of health problems, but more targeted research should continue for diseases such as: Cancer. Preliminary research suggests that vitamin D has an anti-cancer benefit. It may stop the growth and progression of cancer cells and be beneficial during cancer treatment, too.

Hormonal problems. Vitamin D influences the functions of insulin, rennin, serotonin and estrogen—hormones involved with health conditions such as diabetes, blood pressure, heart disease, stroke, depression and premenstrual syndrome.

Obesity. Some research shows that a vitamin D deficiency can interfere with the "fullness" hormone leptin, which signals the brain that you are full and should stop eating.

Inflammation. Vitamin D may help control the inflammation involved with periodontal disease, rheumatoid arthritis and osteoarthritis.

Weakened immune system. Vitamin D may play a role in a strengthening your immune system, especially in autoimmune disorders (when the body attacks itself) like multiple sclerosis and rheumatoid arthritis.

How much vitamin D do you need?

In the last few years, many experts and health organizations urged the Institute of Medicine to revisit the DRI set for vitamin D and re-evaluate the latest research. After a thorough review, the recommendations for vitamin D did go up by two or threefold in some age groups. The current Recommended Dietary Allowance for vitamin D (as of November 2010) is: Ages 1-70: 600 IU (International Units) daily

Ages 71 and older: 800 IU daily

Tolerable Upper Intake Level: ages 9 and up: 4000 IU daily

Are you deficient on D?

Because vitamin D is a fat-soluble vitamin, the body can store it for long periods. Tracking your intake from foods or supplements alone won't determine if you're truly deficient in vitamin D. Moreover, even if you appear to get enough vitamin D from foods or supplements, there is no guarantee that your body is absorbing or using all the D that you appear to be consuming. The only way to know your vitamin D status is to ask your health care provider for a vitamin D test. (It is best to have the test preformed about a month before the beginning of winter.) Your doctor will check your blood level of 25-hydroxyvitamin D. A desirable result for this test, according to the IOM is 20-30 ng/mL (nanograms per milliliter).

The ABC's of Getting Your D

Vitamin D is a key nutrient for everyone and there are three ways to obtain it: from the sun, food or supplements. Here's what you need to know about each source.

Sunlight is an excellent source of vitamin D. It is free and abundant. The ultraviolet B (UVB) rays from the sun convert a precursor into vitamin D, which becomes 25-hydroxyvitamin D in the liver and is then activated to 1, 25-hydroxyvitamin D in the kidneys. A person sitting outside in a bathing suit in New York City gets more vitamin D in 20 minutes than from drinking 200 glasses of milk. In fact, many experts suggest getting 10 minutes of unprotected sun on the arms and face or arms and legs, three times weekly and before applying sunscreen. But getting vitamin D from the sun isn't that simple. UVB rays vary greatly depending on latitude, cloud cover, time of year and time of day. Above 42 degrees north latitude, the sun’s rays do not provide sufficient D from November through February, for example. Remember too, that UVB rays do not penetrate glass or sunscreen with a sun protection factor (SPF) of 8 or more. The elderly, people who spend all or most of their time indoors, and people with darker skin also produce less vitamin D. Talk to your health care provider about unprotected sun exposure; not everyone in the scientific community thinks that even a little sun is a good idea, because of the risk of skin cancer.

Food can provide vitamin D, but it's difficult to get 600 IU of vitamin D from your diet alone. Only a few foods (fatty fish, liver and egg yolks) contain vitamin D naturally. Other foods, such as milk and cereal, are fortified with vitamin D. While the average person gets less than the required amount of vitamin D through their daily diet, few people are showing a deficiency, according to the most recent studies.

Food Source

Vitamin D (IU)

Cod liver oil+, 1 tablespoon 1,360

Salmon, 3.5 oz cooked 360

Mackerel, 3.5 oz cooked 345

Sardines, 1.75 oz canned in oil 250

Tuna fish, 3 oz canned in oil 200

Milk, 1 cup (fortified*) 100

Orange juice, 1 cup (fortified) 100

Soymilk, 1 cup (fortified) 100

Yogurt, 6 oz (fortified) 60-80

Pudding, 1/2 cup (made with fortified milk) 50

Egg, 1 whole (vitamin D found in yolk) 41

Ready-to-eat cereal, 3/4 cup to 1 cup (fortified) 40

Margarine, 1 teaspoon (fortified) 20

Beef liver, 3.5 oz cooked 15

Swiss cheese, 1 oz 12

*Check food labels; not all products are fortified with vitamin D and amount per serving varies by brand.

+Before trying the potent supplement cod liver oil (or any fish oil), check with your doctor because of fish oil's vitamin A content and possible toxicity.

Supplements may be necessary for a few individuals, but check with your doctor first. A multivitamin-mineral supplement typically contains 400 IU of vitamin D. Many supplements contain ergocalciferol, called D2, which is a less potent form of vitamin D derived from the irradiation of yeast; it's also less expensive. You are better off using a supplement that contains cholecalciferol, or D3, made from fish oil, the fat of lamb’s wool (lanolin) or the chemical conversion of cholesterol. This form is much better absorbed by the body, but it can be harder to find and more expensive. (Check the supplement label or inquire with supplement manufacturers to find out whether they use D2 or D3 if the label doesn't specify.) Vitamin D is often added to calcium supplements, or you can also buy a vitamin D supplement by itself. Vitamin D is a fat-soluble vitamin, so take your supplement with a meal containing some fat to enhance absorption.

It is far too early to call vitamin D a wonder drug, but evidence of its importance is mounting. Therefore, you may want to consider this Spark of advice: Aim to get 600 IU of vitamin D daily through your diet. You can track your intake on SparkPeople's Nutrition Tracker to see how well you are doing.

Talk to your health care provider about the need for a vitamin D test, and discuss your test results.

Talk to your health care provider about careful sun exposure—10 minutes on the arms, face, and/or legs, three times weekly—before you slather on the sunscreen.

Talk to your health care provider about a vitamin D supplement or a multivitamin-mineral supplement that contains vitamin D. If you take one, make sure it is the vitamin D3 form, cholecalciferol.

Eat foods rich in vitamin D each day.

Maintain a healthy weight.

Talk to your doctor if you are using the weight loss drug, Orlistat (brand names include Xenical and Alli). This drug may decrease the absorption of vitamin D.

Antacids, some cholesterol lowering drugs, some anti-seizure medications, and steroids (like Prednisone) interfere with the absorption of Vitamin D, so discuss your vitamin D intake with your doctor or pharmacist if you take any of these drugs.

While it's no secret that vitamin D plays a key role in bone health, it's important to note that too much of a good thing can be dangerous as well. Your body stores vitamin D—and those stores can build up to toxic levels if you go overboard. Many people currently ingest large amounts of vitamin D through supplements and fortified foods. Others simply believe that more is better. However, the IOM set a tolerable upper intake level for vitamin D at 4,000 IU per day. You should NOT strive to consume this much vitamin D—this is an upper limit for safety. Too much vitamin D is toxic and will increase your risk of health problems. The key, like many experts advise regarding nutrition, food and health, is making sure you get enough of a this powerful nutrient while avoiding extremes

Beginning an exercise program can be very overwhelming-- even painful if you aren’t careful. Warming your body up prior to exercise is very important for your health (and safety) and will also help you enjoy your workouts more. Warming up for 5-10 minutes will raise your body temperature and prepare your cardiovascular, respiratory, and nervous systems for the demands of exercise by slowly increasing the blood circulation to and from your heart and muscles.

Warming up helps your connective tissues better handle the stress of exercise, decreasing your chance of injury. Connective tissue is similar to hard plastic; if you don’t warm-up plastic it won’t be flexible, and is much more likely to "break."

Proper warm ups (and cool downs) also help reduce the severity of soreness in the next day or two following your workout. The increased blood flow helps deliver more oxygen to the muscles and gets rid of the waste products that contribute to soreness. Increased blood flow also helps bring more fuel to your body, resulting in better performance.

Warm up with a low-impact exercise at a slower, more comfortable pace than your actual workout. Warm up exercises like biking, an elliptical machine, walking, or rowing allow your body to warm up with limited stress to your joints.

Another reason for soreness is trying to do too much too soon. Don’t try to make up for lost time. Start out with a few exercises and slowly progress. Your body will gradually adapt to the increased stress. If you are starting resistance training for the first time, try picking 1-2 exercises for each area of the body - the upper body, lower body and core. Also take into consideration the anterior (front) and posterior (back) parts of the body. For example, if you pick two core exercises, you might try bicycle crunch for the abdominals (front of the body) and lumbar extension for the lower back (posterior part of the body).

If you are a beginner to aerobic training, start out with something like walking that raises your heart rate a little bit, nothing that will get you too out of breath. Try doing this for 10 minutes the first few times you exercise, slowly progressing the duration of the workout. If you've increased the time to a point where you can handle 30 minutes at that pace, start building a little more intensity. For example, you could attempt 2 or 3 days of 30 minutes each at your initial pace, followed by a 10-minute day at an increased intensity.

Another area of frustration for the beginner is energy level. Most people expect to exercise the first few weeks and experience a shot of energy. In actuality, the opposite often occurs. Your body isn’t used to the added stress, which causes you to feel fatigued and even drained, especially if you overdo it. Don’t get discouraged; it’s natural to feel this way until your body adapts. As your body acclimates itself, your cardiovascular system will become more conditioned, causing you to have more energy and focus throughout the day. Your efforts will pay off.

Overexertion will trigger stiffness and soreness, causing many people to give up on exercise completely. If you do overdo it, there are a few things you can do to feel better. Exercise actually breaks your muscles down – sleep, nutrition, and hydration play a vital role in their recovery. Proper rest, refueling your body with healthy food, and drinking plenty of water will help you recover much more quickly. In the days that follow, doing a low impact exercise at a low to moderate intensity and stretching will deliver more oxygen and blood to help clean out the waste and bring more nutrients to your muscles.

Your body loses a large quantity of water when you work out, so it is very important to drink more water as you exercise. Active people should drink at least 10-12 eight-ounce cups a day, throughout the day, taking extra care to rehydrate during the workout. This will keep your joints moving fluidly and flush out the toxins that might be building up in your muscles. Headaches, stiffness, and cramping are all results of dehydration.

There's a lot of free advice about physical activity out there these days − some reliable, some not. It's easy to fall into the trap: A friend gives you an activity tip, and then you pass it on to several buddies you know. One day, you're at your weekly yoga class, and sure enough, you hear the same tip repeated, so you figure it must be true. When you're unsure, the important thing is to ask a qualified fitness professional for advice. In the meantime, knowing the difference between fact and fiction will keep you healthy, injury-free, and on track to meeting your physical activity goals. Here are some myths that need some challenging:

Myth #1: An aerobic workout will boost your calorie burn for hours after you stop working out.

False: Don't confuse calorie burn with metabolism. While your metabolism will continue to rev at a slightly higher rate after you finish an aerobic workout, the amount of calorie burn is not statistically significant. In fact, you'll only use up about 20 extra calories for the rest of the day. While there's a little bit more of a metabolic boost after strength training, it's still negligible. In other words, don't use the fact that you worked out to eat more.

Myth #2: If you're not working up a sweat, you're not exercising hard enough.

False: Sweating or perspiring is not necessarily an indicator of exertion. Perspiring is your body's way of cooling itself. It's possible to burn a significant number of calories without breaking a sweat.

Myth #3: Strength training will make me "bulk up."

False: Gaining muscle mass is something you have to work very hard at to achieve, male or female. Women tend to avoid weight training because they don't want to look bulked up. However, strength training is a critical element to maintaining a healthy weight and strengthening your body. What we know is that the average woman doesn't typically gain bulk from strength training because she doesn't have the amount of hormones necessary to build massive amounts of muscle.

Myth #4: Machines are a safer way to weight train because you're doing it right every time.

False: Although it may seem as if an exercise machine automatically puts your body in the right position and helps you do all the movements correctly, that's only true if the machine is properly adjusted for your weight and height. Before using any equipment or performing any exercise, you should ensure you understand the full mechanics of the movement and the proper endpoints. Unless you have a coach or a trainer to figure out what is the right setting for you, you can make just as many mistakes in form and function and have just as high a risk of injury on a machine as if you work out with free weights or do any other type of workout.

Myth #5: When it comes to physical activity, you've got to feel some pain if you're going to gain any benefits.

False: While you should expect to have some degree of stiffness or soreness a day or two after physical activity, that's very different from feeling pain while you are working out. A fitness activity should not hurt while you are doing it, and if it does, then either you are doing it incorrectly, or you already have an injury. As for "working through the pain," experts advise against it. If it hurts, stop, rest, and see if the pain goes away. If it doesn't go away, or if it begins again or increases after you start an activity, see a doctor.

Myth #6: If I can't be active often enough, I might as well not even do it.

False: Remember: Any activity is better than no activity, even if it's only a 15-minute walk. Being physically active is important for heart health and is proven to reduce stress. So, even if you can't make it to the gym or yoga class, you can always do something active each day. Taking a walk, climbing the stairs instead of hopping on the elevator or escalator all count!

Myth #7: You can take weight off of specific body parts by doing exercises that target those areas.

False: This concept is called "spot training" and unfortunately, it doesn't target fatty areas. When you lose weight, your body predetermines which fat stores it will use. For example, doing sit-ups will strengthen your abs but will not take the fat off of your stomach. Similarly, an activity like running burns fat all over your body, not just your legs. You can, however, complement a balanced physical activity program with a selection of weight training exercises to gradually lose weight and tone your body.

Myth #8: You will burn more fat if you exercise longer at a lower intensity.

False: The most important factor in physical activity and weight control is not the percentage of fat calories burned, but the total calories burned during the activity. The faster you walk, bike or swim, for example, the more calories you use per minute. You may still be burning more calories (and likely will be) from fat but the relative percentage of the source will be altered. So high intensity exercises will likely burn more calories total, as well as attributable energy to fat metabolism.

Myth #9: I can eat what I want because my workout will keep the weight off.

False: If you tend to eat large-portion meals such as 340 g/12 oz steaks, two to three cups of pasta, three to four slices of pizza, or high-calorie foods such as chocolate shakes and fries on a regular basis, no manner of workout will burn enough of those calories off to keep your weight in check. A healthy way to achieve and maintain a healthy weight is to combine healthy eating with regular physical activity – they go hand in hand. Need help? Try our Healthy Weights Action Plan.

Myth #10: The best time to be active is early in the morning.

False: There is no one optimal time to be active. The best time is the time that appeals to you and fits into your schedule on a regular basis. Some folks love to jump-start their day with a morning workout, while others swear that physical activity at the end of the work day is a great way to boost energy for the evening and eliminate stress. Choose whatever works for you.

Before starting any activity program, be sure to talk to your doctor or other healthcare professional.

This physical activity column was written by a certified personal trainer and fitness instructor and reviewed by a specialist in kinesiology.

Provided by Heart and Stroke Foundation.