Vitamin D: What’s the Big Deal?
What’s the big deal with vitamin D? More and more people are being told they are low by their doctors. Our mind races immediately to: “What does that mean? What will happen if I don’t fix it? How did it get low to begin with? I thought that came from the sun – I’m always in the sun!” This article aims to answer these questions for you and to help you have a better understanding of “the sunshine vitamin”, especially as it pertains to patients who have bariatric surgery.
Why do I need vitamin D?
Vitamin D is a vitamin we need in order to absorb calcium. It regulates calcium and phosphate in our bodies in order to have healthy bones, teeth, and muscles. There is data showing adequate vitamin D may help prevent certain cancers, maintain a healthy mental mood, impacts neuromuscular function, and enhance the immune system as well.
How common is vitamin D deficiency?
Vitamin D deficiency is the most common vitamin deficiency in developed countries. The prevalence is estimated at 42% of adults. Being from a non-white race, having obesity, high high-density lipoprotein (HDL) cholesterol, and no daily dairy consumption are all associated with low levels.
What causes vitamin D deficiency?
There are several causes of low vitamin D levels. Sun exposure helps our body make vitamin D, and many of us are now using sunscreen to limit our risk of skin cancer and aging. Our free time is also spent more indoors than outdoors for a lot of us, having significantly more technological forms of entertainment than we did when we were kids. Unfortunately our skin’s production of vitamin D declines naturally with age, as well, so even if we are out in the sun a lot, we don’t make vitamin D like we used to. Lower levels are frequently found in persons who live in the northern part of the world, and patients with darker skin also may have decreased vitamin D production.
Dietary vitamin D is also generally decreased as our intake of dairy products has declined over the years. There is a significant link between obesity and vitamin D deficiency which is not clearly understood. Some scientists believe that having obesity may make people resistant to its absorption.
Persons with malabsorption, including celiac disease and inflammatory bowel disease, are at a higher risk of deficiency, as are patients taking medications that speed up the breakdown of vitamin D, such as phenytoin.
What happens if you are low in vitamin D?
The clinical manifestations of vitamin D deficiency depend on how severe the deficiency is and how long it has been low. Most patients whose deficiency is mild to moderate will not display any symptoms. That does not mean that it is not harmful; it just means you don’t realize what’s happening inside your body.
Roughly 50% of patients low in vitamin D will have high Parathyroid Hormone (PTH). (The parathyroid glands are NOT related to your thyroid; they just sit next to it.) Patients who have elevated PTH and low vitamin D are at an increased risk for accelerated bone loss, which can lead to decreased bone mineral density and subsequent fractures.
Patients low in vitamin D for an extended period of time have reduced absorption of calcium and phosphorus in their gut. This also leads to weakening of bones. These patients notice bone pain and tenderness, muscle weakness, bone fractures, and difficulty walking.
Vitamin D may have an important effect on many other cellular functions, including the immune, cardiovascular and metabolic systems. Researchers are currently looking into these possible connections to learn more.
How do I know if I’m low in vitamin D?
Your doctor can check your level with a blood draw. It is typically measured using serum 25-hydroxycholecalciferol. Your physician may also check your levels of calcium and parathyroid hormone to get a more complete picture.
How much vitamin D do I need?
The average adult needs 600-800 IU of vitamin D daily. Older persons or other high-risk groups may need higher intakes. Some who are resistant to vitamin D may need significantly higher doses.
Your doctor will guide you on how much you need to take. Some patients are resistant to supplements and need high doses, while others respond well to lower doses. Your doctor will guide you in this regard. In patients with significant deficiencies, a high dose may be recommended to take weekly. We recommend cholecalciferol (vitamin D3) over ergocalciferol (vitamin D2) because of improved absorption.
All patients should also maintain a daily calcium intake of 1000-1200mg, or 1500mg if you have had bariatric surgery. This should be divided into 3 doses to maximize how much you absorb.
When should I take my vitamin D supplement?
Vitamin D is a fat-soluble vitamin, meaning it does not dissolve in water. It is best absorbed when you take it with food that has a little fat in it, like avocado, nuts, seeds, dairy and eggs. Remember not to break your fast between your meals for your vitamin, though; just take it with your regular meals.
What foods contain vitamin D?
Fish such as salmon, tuna, and mackerel, as well as cheese, mushrooms, and egg yolks are high in vitamin D. It’s not everyone’s favorite food, but beef liver also boasts high levels of this important vitamin.
Many foods are fortified with vitamin D. Milk, orange juice, dairy products such as yogurt or cottage cheese are frequently fortified as well. (Remember that liquid calories such as milk and juice are not recommended as part of a bariatric eating plan.)
If you have a vitamin D deficiency, you are unlikely to get adequate amounts from diet alone. Supplements are usually necessary to bring your levels up to normal. Continued monitoring is necessary to ensure your levels stay within a normal range.
How does Bariatric Surgery affect Vitamin D?
Studies show that 100% of bariatric surgery patients need vitamin D supplementation in order to maintain normal levels. Bariatric surgery patients eat smaller volumes of food and absorb vitamins differently than before. Patients with gastric bypass may need higher doses than sleeve gastrectomy patients. Most bariatric surgery patients require daily doses of 1000 – 5000IU daily.
If my calcium level is normal, doesn’t that mean that I have healthy bones and don’t need to worry about my vitamin D?
Your body needs calcium for many things, including pumping the heart. For this reason, if your body does not get enough calcium from diet or supplements, it will pull it from your bones to keep your blood level normal. This can cause weak bones. So a normal blood calcium level does not mean you have healthy bones.
The same is true for the relationship between vitamin D and your calcium. If you are vitamin D deficient, you cannot absorb calcium well. So again your body will have to pull calcium from your bones, resulting in weak bones.
What does the parathyroid hormone have to do with it?
Usually when the body is needing more calcium, either because of poor calcium intake or because of low vitamin D levels, it will increase the production of Parathyroid Hormone (PTH). Elevated PTH can be an indicator that calcium is being pulled from the bones and that we need to fix the vitamin D deficiency and get in adequate calcium.
Can you get too much vitamin D?
You can get too much vitamin D. It is a fat-soluble vitamin so you will not just urinate out excess like you do with some vitamins. Signs of overload, or toxicity, include nausea, vomiting, poor appetite, constipation, weakness, and weight loss. Excess amounts can be harmful to your kidneys and can cause elevated calcium in your blood. This can result in heart rhythm problems, abdominal pain, kidney stones, confusion and disorientation.
How can I keep my bones healthy?
Maintaining adequate calcium and vitamin D intakes is key, but there are other ways to help your bones stay healthy. Bone-building exercises can have a great impact on your bones’ health. Bone-building exercises are weight-bearing. Examples include walking quickly, jogging or running, jumping rope, climbing stairs, tennis, hiking, dancing, aerobics, stair-step machine, elliptical, lifting weights, elastic/resistance bands, yoga and Pilates.
Vitamin D is necessary to keep you healthy on many levels. Make sure you get your levels checked at least once a year and adhere to the recommended intake amounts. For more information about nutrition post bariatric surgery, see our Nutrition Guide.