Posts Tagged ‘Vitamin D’
October Light…
Every year when the weather turns, I do this. Basically, because I can’t believe I’m still here. Don’t get me wrong, the Northwest is an absolutely gorgeous place and Portland has everything I could ever want in a city. But I simply… Love. Sunshine. The lack of it makes me wilt after awhile.
Behind the Scenes… “You… The Distance Runner”
I found this article particularly comprehensive relating to diet, bone health, and iron issues in competitive distance runners…
Distance Running
excerpted from:
http://www.healthline.com/hlbook/nut-distance-running
To go long distances, especially those longer than 10,000m, runners place a premium on relying primarily on aerobic metabolic pathways during the majority of the run. Runners who are capable of doing this rely mainly on fat for the majority of fuel, enabling them to limit the usage of carbohydrate. Carbohydrate storage is finite, but fat storage is, from a practical standpoint, limitless. The higher reliance on fat enables long-distance runners to run very long distances. It also enables them to preserve carbohydrate for moments during the race when they require fast acceleration (e.g., at the end of the race or while passing another runner). According to one study, only 2 to 7 percent of the total energy burned in aerobic activity is derived anaerobically.24 A small amount of carbohydrate is used even when maintaining aerobic activity, so distance runners must develop strategies for delivering carbohydrate during the run. A failure to do so will result in either low blood sugar or low muscle glycogen, both of which impair endurance by leading to premature muscle fatigue.
Keeping this in mind, distance runners must consider the following nutritionally relevant factors for their sport.
Long-distance runners are at risk of amenorrhea, low bone density, and stress fractures. The distances that these athletes run weekly to train may predispose them to stress fractures, despite the potential stimulating impact of running on skeletal mass.25 Although stress fractures occur more frequently in women runners than in men, all runners should ensure that their calcium intake is adequate to reduce the risk of fracture. Female runners are at higher risk of stress fractures because hard endurance training is often associated with cessation of the menstrual cycle. The reduced estrogen associated with amenorrhea is linked to lower bone density. Therefore, runners who experience either primary or secondary amenorrhea should seek appropriate medical advice to determine if rea son able steps can be taken to return to normal menstrual status.26
Female runners should take the following steps to reduce the risk of osteoporosis:
Consume calcium (1,500 milligrams per day) from food or a combination of food and supplements.
Avoid overconsumption of protein because excess protein is associated with higher urinary calcium losses.
Control the production of stress hormones (particularly cortisol) by maintaining hydration and blood sugar during exercise.
Avoid overtraining, which is associated with amenorrhea.
Inadequate energy intake is a red flag that the intake of vitamins and minerals may also be low. A study comparing the nutrient intakes of trained female runners who were amenorrheic, oligomenorrheic, or menstruating normally found clear nutrition differences between these groups, despite being matched on height, weight, training distance, and body fat percentage.27 The runners who were not menstruating had zinc intakes well below the recommended level of intake and lower than those found in the runners who had normal menses. In addition, the runners who had normal menses had higher intakes of fat and a more adequate total energy consumption. This suggests that high-carbohydrate diets, which are preferred for optimal performance, make it more difficult to consume the needed level of energy because carbohydrates have a lower caloric density than high-fat foods. Therefore, athletes should concentrate on consuming more food when carbohydrates constitute the main energy source. A failure to menstruate normally is a strong risk factor in the development of weaker bones and resulting stress fractures. Female runners have good cause to be fully aware of the adequacy of their energy and nutrient intakes because almost no injury is more frustrating or potentially career ending than the development of frequent stress fractures. Endurance runs require enormous amounts of energy (a marathon requires about 2,900 calories); they cannot be adequately trained for or run without an adequate total energy consumption. Food intake strategies, including eating snacks between meals and consuming snacks or sports beverages before, during, and after exercise, are important for ensuring that fuel consumption matches need.
Elite runners depend heavily on both fat and carbohydrate for fuel to accelerate and vary speed over the course of a long-distance race.
Surveys of distance runners confirm that total energy and carbohydrate intakes are below the recommended levels, suggesting that runners must make a concerted effort to consume the recommended amounts before, during, and after exercise.28,29 In a case study assessing the nutrient intake of an ultraendurance runner during a race, it was found that if the pre-event and during-event guidelines for food and beverage are followed, then athletes will have sufficient energy and fluids to successfully complete the event.30
Tapering activity before a competition improves competition performance.31 It does so by increasing glycogen stores, but it also makes the runner calmer, which gives the athlete an improved economy of running motion that enhances endurance. The importance of tapering exercise and of carbohydrate loading before an important event cannot be overemphasized.
Fluids are crucial. Fluid consumption should be on a fixed time schedule (every 10 to 15 minutes) to avoid underhydration and thirst. Perhaps no single factor is more important for ensuring a long-distance runner’s success than maintaining an optimal hydration state. Athletes should drink now, drink again in 10 to 15 minutes, and when they believe they’ve had enough, they should drink
more. Of course, the type of beverage consumed is also important.
A great deal of body heat is generated over the course of an endurance run, and this heat is liberated through sweat evaporation. Studies strongly suggest that a 6 to 7 percent carbohydrate solution with electrolytes is most effective in maintaining exercise endurance.31 It has been firmly concluded that acute heat exposure is detrimental to muscular endurance.32 Therefore, long-distance runners should develop the habit of frequent fluid consumption to maintain body water status, whether they are thirsty or not. A fluid intake of .5 to 1 liter per hour is sufficient to prevent significant dehydration in most athletes in mild environmental conditions, but a greater intake of fluids is needed for athletes running at higher intensities or in more severe environmental conditions in order to avoid heat stress.33
Distance runners typically have relatively low body fat levels. Successful long-distance runners are commonly thin, and this body profile may be advantageous to them in dissipating heat during long runs.34 However, since very low body fat levels are associated with amenorrhea, female athletes should seek a balance between low body fat levels and normal hormone function.
A critical factor in the performance of all endurance athletes is iron status, and evidence exists that endurance runners have reduced hemoglobin, hematocrit, and red blood cell counts when compared with strength and mixed-trained athletes.35 Iron status is sufficiently important that one of the more common illegal ergogenic aids used by endurance runners is erythropoietin (EPO),36 which stimulates the production of red blood cells, thereby enhancing oxygen-carrying capacity.37 Iron is an essential oxygen-carrying component of hemoglobin (red blood cell iron), myoglobin (muscle cell iron), and ferrochromes (oxygen-carrying enzymes essential for making ATP) in the mitochondria. It appears that hemoglobin status is of highest priority, so iron from other cells is cannibalized to support a normal hemoglobin production when iron stores (ferritin) and intake are inadequate. Therefore, a standard blood test measuring hemoglobin may appear normal while other iron-containing cells are depleted. For this reason, it is important that blood tests in endurance athletes always include a measure of ferritin, which should be at the level of a minimum of 20 nanograms per deciliter. Besides having an inadequate dietary intake, which is most common in runners who do not eat red meat or who are vegetarian, there are several other common causes of low iron status in runners:38-40
Excess iron loss in sweat
Excess loss of blood through the GI tract
Excess loss of blood in the urine (hematuria)
Excess menstrual blood loss in female runners
Poor absorption of iron
Intravascular hemolysis
Calcium & Vitamin D May Reduce Stress Fracture Risk
http://www.nutraingredients-usa.com/Research/Calcium-vitamin-D-may-reduce-stress-fracture-risk
12-Feb-2007 –
Daily supplements of calcium and vitamin D, long linked to improving bone health, may also reduce the risk of stress fractures during exercise, scientists have reported.
The results, presented yesterday at the 53rd annual Orthopaedic Research Society meeting in San Diego, were obtained from a randomized, double-blind study with 5,201 female U.S. Navy recruits during eight weeks of basic training.
“What really surprised us is that calcium/vitamin D supplements made a significant difference in such a short period of time. Frankly, we were not sure we would see any statistically significant results in only eight weeks,” said lead researcher Joan Lappe from Creighton University in Omaha.
The combination of vitamin D and calcium has long been recommended to reduce the risk of bone fracture for older people, particularly those at risk of or suffering from osteoporosis, which is estimated to affect about 75m people in Europe, USA and Japan.
The action of the nutrients is complimentary, with calcium supporting bone formation and repair, while vitamin D helps the body absorb calcium.
The new study, funded by the U.S. Department of Defense, appears to suggest that daily supplements of the vitamin and mineral may also provide benefits for those engaged in athletic training.
Stress factures are said to be one of the most common and debilitating overuse injuries seen in U.S. military recruits with 21 per cent of female recruits reported to suffer from this form of injury. Male recruits suffer less.The research of Professor Lappe, presented to attendees in San Diego, divided the recruits into two groups – one group received a daily supplement of 2,000 Mg of calcium and 800 IU of vitamin D, and the other group received a placebo.
At the end of the eight weeks of basic training, 170 women in the placebo group experienced stress fractures; 25 per cent more women than in the calcium/vitamin D supplemented group. NutraIngredients.com has not seen the full data.
“It appears that supplementation with calcium and vitamin D provides a health-promoting, easy and inexpensive intervention that does not interfere with training goals,” said Lappe.
Further studies are needed to confirm these findings, but the results appear to fit with numerous other studies linking the nutrients to improved bone health.
The current EU recommended daily intake of calcium is 800mg, with an upper safe limit of 2500mg. Vitamin D has a RDI of 400 IU, although campaigners are calling for an increase to 1000 IU, half the upper safe limit recommended by the EU and US.
In the US, the DRI (dietary reference intake) for calcium is 1000mg for adults aged 19 to 50, and 1200mg from 51 to 70. For vitamin D it is five micrograms per day, rising to 10 after the age of 50.
Pill Popping… a sample daily intake
Morning:
Levoxyl- on empty stomach of course… sometimes I’ll set my alarm and go back to sleep.
Midday or later morning:
Vitamin D
Zinc
Omega 3
L-Tyrosine (Thyroid support)
Kelp (Thyroid support)
Before Bed at Night:
Iron
B-Complex
Vitamin C
Rhinocort Aqua Nasal Spray (for my allergies)
I don’t take a multi because I don’t like having everything in one pill. It is convenient though! I just want to make sure that I give myself a fighting chance at absorbing everything… especially since my intestines are in a rough shape.
Any to add?
You Are My Sunshine…. Vit D
This morning felt so cold, I couldn’t believe it. And all day has been cloudy so far. Just another reminder to swallow those Vitamin D pills when I get home tonight from my long day up on the hill.
Up until about a year ago, I never paid Vitamin D much attention. All I really knew was the basics:
- it works along with calcium and magnesium for bone health
- your body makes it from sunshine
- it’s added to pasteurized milk in this country
- it’s fat soluble like Vitamin A- which means you can overdose because your body stores it instead of excreting it through sweat/urine.
Pretty much all common knowledge. It wasn’t until I went down to see the Endo in Houston that I learned that I had a severe vitamin D deficiency. (I found this very ironic, since until I moved to the Pacific Northwest, I felt like I spent my life baking in the sun.) That news meant, of course, that I had to find out more. And much to my surprise, this is one fascinating nutrient.
I’ve read that Vitamin D deficiency has been linked to iron deficiency. The reason may be that individuals who are iron deficient have trouble metabolizing Vitamin D…. but I think that it is likely more of a correlation than causal relationship. Persons with fat malabsorption often have Vitamin D deficiencies, meaning that it requires some dietary fat for absorption. Symptoms of fat malabsorption include diarrhea and oily stools… (sorry again to be graphic). Fat malabsorption is associated with a variety of medical conditions including… drum roll please: CELIAC DISEASE. And, like I mentioned before, people with celiac or other malabsorption problems (like Crohns, etc.) are also very likely to have iron deficiency.
On another point high caffeine intake (300mg/day, which is equivalent to 18 oz of regular coffee) inhibits both vitamin d and iron absorption from the diet. Just another reason for me to cut back… (it is just sooo hard! Starting tomorrow!)
BUT… diet is not the best way to get vitamin D anyways. Our bodies prefer to make it from the sun. 10 to 15 minutes of sun exposure at least two times per week to the face, arms, hands, or back without sunscreen is usually sufficient to provide adequate vitamin D. Of course, this news flies in the face of the recommendations of your dermatologist- all of whom push the sunscreen. Unfortunately, if you are slathering on the sunscreen (spf 8 and higher) you’re blocking the UV rays that your skin needs to produce the required amounts of Vitamin D.
Hmmmm…. skin cancer or rickets?
Just kidding.
What makes the sunlight issue more difficult is that many of us live in Northern latitudes where the angle of the sun and weather patterns hamper our best efforts to tan. Also playing a role are season, time of day, cloud cover, and smog, affect UV ray exposure and vitamin D synthesis. For example, sunlight exposure from November through February in Boston is insufficient to produce significant vitamin D synthesis in the skin. Complete cloud cover halves the energy of UV rays, and shade reduces it by 60%.
According to the National Weather Service’s data for the period between 1951-1995. There was an average of 67 clear days per year. That’s it. 71 days were partly cloudy and a whopping 227 days were ENTIRELY CLOUDY!!!!
I am severely deficient in Vitamin D and I get outside to run every day, and I’m fair-skinned (the more pigment in your skin, the more sun it takes to make adequate amounts of vit D). It is hard to imagine how anyone here could be high without a supplement.
So, why does any of this matter?
There have been hosts of more recent studies that have linked high levels of vitamin D in the body to much decreased incidences of cancer, autoimmune diseases, and Alzheimer’s, among others. What is very interesting is that the levels needed for this kind of disease prevention are far above those needed merely for optimal bone health. These findings have led to an increased awareness of the nutrient and talks to increase the federal government’s RDA, which is currently a pathetic 200 IUs for adults under 50.
One of the most interesting tidbits for me is that Vitamin D functions more like a hormone in your body than it does like an actual vitamin. It affects your calcium absorption, thyroid, and immune system.
There are two types of Vitamin D commonly available in pill form: D2 and D3. D3, or cholecalciferol, has been found to be up to 10 times more potent that equal amounts of D2. The problem for vegans is that D3 is made from an animal source (Lanolin, which is derived from sheep’s wool). D2, on the other hand, is made from yeast and perfectly suited to vegans.
The upper limit for consumption of Vitamin D (D3) is about 2,000 IUs per day for adults. If you are deficient, your doctor will probably tell you to take more, or prescribe a 25,000 IU tablet that you take once per week.
In order to achieve the full benefit of the nutrient, many experts are recommending supplementing with 1,000 IUs of D3 per day.
Just please don’t use it as an excuse to drink more gross cow’s milk. The benefits of your increased vitamin D intake would come no where near to outweighing the health risks…. not to mention the acne and phlegmy mucus… but that is another post entirely.
