- Published: November 12, 2022
- Updated: November 12, 2022
- University / College: Queen's University at Kingston
- Language: English
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Elizabeth BeaverDietetic StudentDepartment of Nutritional SciencesCollege of Allied HealthUniversity of Oklahoma Health Sciences CenterMarch 4th, 2013OutlineIntroductionVitamin D Background (Understanding What is Adequate Intake)FactsSourcesDeficiencyRisk FactorsToxicityHeart Disease BackgroundDefinitionFactsRisk FactorsPrevention and TreatmentPreventing Heart Disease with Vitamin DVitamin D and Heart Disease RelationSupplementation of Vitamin DVitamin D deficiency: Risk Factor for Heart DiseaseImplications for RD’sNutritionPrevention and TreatmentScreenings and OutcomesConclusion
In adults 18-65, does adequate oral intake and photosynthesis of vitamin D prevent heart disease?
The importance of vitamin D has been a hot topic as of late in the RD world making it a prime target for research. From this increased interest, there have been possible linkages to cancer, high blood pressure, osteoporosis, and several autoimmune diseases with vitamin D deficiency (1). If this is so, vitamin D can become a major factor for prevention in the medical field. This fat-soluble vitamin helps with the absorption of calcium, is needed for bone growth, maintains serum levels of phosphate and calcium, regulates cell growth, has neuromuscular and immune function, and reduces inflammation (2). Understanding these functions is not only important for RD’s but for all health care providers. All the roles that vitamin D plays in our bodies may be a key factor in preventing many diseases specifically heart disease. In order to understand the correlation between vitamin D and heart disease, information over vitamin D and heart disease most be covered. Vitamin D has a variety of functions in our bodies that are important for health and development. This vitamin may enter the body in a few different forms as vitamin D is a general term for all forms, but these forms are then converted in the kidneys to the active form calcitriol (1, 25(OH)2D) (2). While in this state, vitamin D is able to perform its tasks and reacts to several vitamin D receptors located in most of the cells and tissues of the human body including cardiomyocytes (3). Vitamin D is in food, supplements and photosynthesized from the sun. The Recommended Dietary Allowances (RDAs) for adults aged 18-65 are 600 IU (15mcg) (2). Two forms are available in both dietary supplements and food, ergocalciferol (D2) and cholecalciferol (D3) (2). Both forms are able to create 1, 25(OH)2D with no major difference between the formations. The major food sources include fatty fish, cod liver oil, fortified milk, and fortified orange juice. Egg yolks, cheese, and other fortified products contain smaller amounts (2). It is often times difficult to consume the necessary daily needs through food since not many people consume cod liver oil or fatty fish daily. A common health problem in the 1930s was the vitamin D deficiency, rickets. In order to increase the consumption, the United States began fortifying milk with 100 IU of vitamin D per cup (2). Supplements are recommended by the American Academy of Pediatrics (AAP) for those who do not receive enough vitamin D and infants who are breastfeeding exclusively and partially (2). The human body can also make vitamin D through photosynthesis by standing outside in the sun for only ten minutes (1). Ultraviolent B (UVB) radiation ” penetrates uncovered skin and converts cutaneous 7-dehydrocholesterol to previtamin D3, which in turn becomes vitamin D3″(2). Different factors contribute to the quantity of the vitamin created in the body such as sunscreen, time of day, weather, skin melanin content, and season. The majority is synthesized on the cheeks and the back of the hands. The key word to synthesizing vitamin D is outside because UVB radiation cannot penetrate through glass (2). This means that being exposed to sunlight through a window of a building or car will therefore not create vitamin D. Tanning booths however emit UVB radiation allowing for the photosynthesis of vitamin D. A randomized study showed that after one full body tanning session, there was a significant increase of 25(OH)D (calcidiol) serum levels after seven days of exposure (p <0. 01) (4). Typical vitamin D deficiencies are rickets and osteomalacia. While the term rickets is used with children, osteomalcia is the terminology used when an adult is vitamin D deficient. The bones soften when there is a lack of vitamin D and often people feel muscle weakness, a widespread bone pain, and numbness around the mouth, arms and legs when they have osteomalcia (5). Misdiagnoses of vitamin D deficiency as fibromyalgia is a common occurrence since the symptoms are roughly very similar (6). Treatment for this vitamin D deficiency is supplementation of vitamin D, calcium and phosphorous (7). General risk factors for vitamin D inadequacy include dark skin, breastfeeding infants, older adults, limited exposure to the sun, obese, fat malabsorption, post-menopausal women, and gastric bypass surgery participants (2, 3). The reason why people with dark skin are at risk is because their skin contain greater amounts of melanin which reduces the ability for the body to create vitamin D. Studies have shown that obese people have lower serum 25(OH)D levels than people who are not obese because of the extra amount of subcutaneous fat that isolates the vitamin causing the release to be altered. For those participants who have undergone gastric bypass surgery have their absorption of vitamin D hindered because of the removal of a small part of their upper small intestine where the absorption of vitamin D occurs (2). Consuming greater amounts of 4, 000 IU can cause hypervitaminosis D that causes abnormally high levels of calcium in the blood (8). This can cause constipation, muscle weakness, fatigue, dehydration, and a decrease in appetite. With continued high doses complications such as kidney stones, dehydration, and hypercalcemia can lead to damages of the kidneys, bones, and soft tissues (2, 8). As most of us has heard, the leading cause of death for both men and women in American is heart disease, not cancer, HIV, or AIDS. About 600, 000 (one in four) people are victims of heart disease (9). This disease can affect people of all ages and ethnicity and is a serious complication that should not be taken lightly. Heart disease occurs when the build - up of plaque narrows the small blood vessels supplying blood and oxygen to the heart (10). This causes blood and oxygen deprivation of the heart that leads to the loss of muscle function and/or death in the muscle. Heart disease is a general term that refers to several different conditions of the heart, but coronary heart disease is the most common heart disease in the United States with 385, 000 deaths annually (9). Most Americans have one of the three top risk factors for heart disease which are smoking, high blood pressure, and high LDL cholesterol. Other common risk factors include diabetes, overweight and obesity, poor diet, physical inactivity, post-menopausal women, and excessive alcohol use (10). Currently the main prevention of heart disease for all ages are eating a healthy balanced diet and regular physical exercise (11). The American Heart Association recommends a healthy balanced diet as foods low in cholesterol, saturated fat, trans fat, sodium, and added sugars and sweeteners. The diet most also contain lots of fruits, vegetables, fiber-rich whole grains, fish, beans, legumes, and seeds (11). Recommendations for physical activity include 150 minutes of moderate activity weekly such as brisk walking or 75 minutes of vigorous activity weekly such as running (11). Treatment includes American Heart Association recommendations as stated above, medications, and lifestyle changes such as a cessation of smoking, limiting alcohol, and controlling diabetes (11, 12). Besides vitamin D’s vital role in our bones and cells, an increasing interest in vitamin D preventing heart disease has occurred over the past five years. Vitamin D has been associated with hypertension because of the biological effects vitamin D has on the heart muscle, renin-angiotensin-aldosterone system, and parathyroid hormone (13). Another association between vitamin D deficiency and heart disease is both conditions contain risk factors of post-menopausal women and obesity. Schierbeck et al. investigated the relationship between vitamin D deficiency and heart disease in recent post-menopausal, healthy women (14). This 16 year follow up study had 2016 participating women who were educated individually by a trained dietitian over portion sizes and vitamin D and calcium sources. At the end of the study, those who were vitamin D deficient had higher instances of heart disease (14). Another relation between the two conditions have been created by ecological studies showing higher prevalence of heart disease around the world the further away people are from the equator which could be attributed to a decrease in photosynthesis of vitamin D and a higher increase in vitamin deficiency (3). A study conducted by Wang et al. assessed the relationship between vitamin D deficiency and the risk of heart disease. There were 1, 739 participants conducted in this study who were the offspring of a previous heart study called the Framingham Heart Study (15). The offspring was roughly around the age of 59 and over half female with no prior cardiovascular disease. 25-(OH)D serum levels were evaluated at the start of the experiment. " The mean 25-(OH)D concentration was 19. 7 ng/mL" and the " overall prevalence of 25-(OH)D <15 ng/mL was 28%, with 9% having 25-(OH)D <10 ng/mL" (15). After a mean follow up of 5. 4 years, 120 participants developed their first cardiovascular event. 55 of these participants where women. The data showed that participants with the highest rate of heart disease also had hypertension and vitamin D deficiency. These results are significant in relating heart disease and vitamin D deficiency (15). This could possibly mean that deficiency in vitamin D may be a risk factor for heart disease. The study did state that further research needs to be conducted in order to figure out if reversal of this deficiency can provide prevention for heart disease (15). Even with recent evidence identifying vitamin D deficiency as a risk factor for heart disease, vitamin D supplementation has not been researched as much. Though there are a few studies that provide insight into supplementation preventing heart disease. In a trial conducted in Australia, participants were either given 1000 IU/d of vitamin D and calcium or a placebo pill and 1000 IU/d of calcium. The participants who received the supplementation of vitamin D had a significantly lower risk for ischemic heart disease (16). An observational retrospective study conducted at the University of Kansas Hospital using a cohort of patients to compare supplementation of vitamin D and vitamin D deficiency with heart disease. There were 10, 899 participants were aged 58 ± 15 years, had a body mass index of 30 ± 8 kg/m2, and 71% of them were female (17). Their serum 25-(OH)D was evaluated at the beginning of the study and five years later. Of the supplementing participants, 29. 7% were within normal levels for vitamin D while the remaining 70. 3% were deficient (17). After five years, the study concluded that vitamin D deficiency was related to several heart diseases including hypertension, cardiomyopathy, and coronary artery disease (all p < 0. 05) and a reduced survival rate of heart disease. Supplementing vitamin D had lower risk of heart disease, but also found an increase in survival of heart disease (p <0. 0001) (17). Brondum et al. conducted a population-based study to link low serum levels of vitamin D with several heart disease. The population-based study was conducted using 10, 170 participants from a Danish population without fortification of vitamin D foods. Of those participants, 4, 725 developed a type of heart disease and 6747 died an early death due to heart disease (18). Most of these people had lower levels of vitamin D in the blood. The data correlated higher instances of heart disease to low serum levels of vitamin D which means that there is an increasing risk of heart disease with vitamin D deficiency (18). Research over vitamin D or heart disease is important for RD’s in our scope of practice. Their main focus is nutrition and all things related to nutrition. Since vitamin D is a fat soluble vitamin and nutrient, any research over this topic is relevant for them to know. Heart disease can be of nutritional relevance because diet is a major prevention of heart disease. Hospitalized patients with heart disease will most likely be seen by an RD and educated over the importance of a healthy heart diet. This new evidence relating vitamin D and heart disease prevention could be crucial information for practicing RD’s in the future as this could be used to prevent heart disease and possibly even reverse the effects of heart disease. Screens for vitamin D deficiency could be used as a way to reduce risk of heart disease. By catching this risk factor early, there may be a possible outcome of lower instance of heart disease. Ideally this would cause heart disease to no longer be the leading cause of death in America. As new research grows in popularity for vitamin D, new findings suggest that vitamin D may play an important role in prevention of several diseases besides the function in bone growth. This could be a turning point in the medical field. From this stand point, adequate serum levels of vitamin D offers a possible prevention for heart disease. Vitamin D is vital for bone growth, cell growth, immune function, and now a possible prevention for heart disease. There is still a need to further research the linkage before providing a set amount of dosage to provide to at risk groups, however, this is a step in the right direction (3). This step could even be some positive signs for vitamin D reversing the affects and consequences of heart disease. Before this can be proven, more research needs to be conducted on this topic however to fully link the reversal effects of heart disease to vitamin D(?).