Vitamin D Prevent Heart Disease

Published Date: 02 Nov 2017

Elizabeth Beaver

Dietetic Student

Department of Nutritional Sciences

College of Allied Health

University of Oklahoma Health Sciences Center

March 4th, 2013

Outline

Introduction

Vitamin D Background (Understanding What is Adequate Intake)

Facts

Sources

Deficiency

Risk Factors

Toxicity

Heart Disease Background

Definition

Facts

Risk Factors

Preventing Heart Disease with Vitamin D

Implications for RD’s

Conclusion

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 of late in the RD world making it a prime target for research. From this increased interest, there has been a possible linkage 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 prevention factor 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.

Vitamin D has a variety of functions in our bodies that are important to our 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 than 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. UVB radiation cannot penetrate through glass so exposure to sunlight through a window will therefore not create vitamin D (2). Tanning booths however emit UVB radiation allowing for the photosynthesis of vitamin D. A randomized study showed that after one full body tanning session had a significant increase in 25(OH)D (vitamin D) 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 most often people feel muscle weakness, a widespread bone pain, and numbness round the mouth, arms and legs when they have osteomalcia (5). Misdiagnoses of vitamin D deficiency as fibromyalgia are not uncommon 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 the extra amount subcutaneous fat isolate the vitamin. Participants who have undergone gastric bypass surgery are missing a small part of their upper small intestine which hinders the absorption of vitamin D (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 and not cancer, HIV, or AIDS. About 600,000 (one in four) people are victims of death from 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). As a result of blood and oxygen deprivation to the heart, the muscle to lose function and/or die. Heart disease refers to several different conditions of the heart, but coronary heart disease is most common heart disease in the United States with 385,000 deaths annually (9). Most Americans have one of the top three risk factors for heart disease which are smoking, high blood pressure, and high LDL cholesterol. Other common risk factors include diabetes, overweight, obesity, poor diet, physical inactivity, post-menopausal women, and excessive alcohol use (10). It is important for RD’s and all health care providers to help with possible ways to prevent heart disease for future generations to come.

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 (11). Another association is risk factors post-menopausal women and obesity are both related to heart disease and vitamin D deficiency. Ecological studies has shown around the world a higher prevalence of heart disease 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. 1739 participants were the offspring of a previous heart study called the Framingham Heart Study (12). 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" (12). 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 (12). 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 of heart disease (12).

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 and in the possible supplementation preventing heart disease. In a trial conducted in the Australia, participants were either given 1000 IU/d of vitamin D and calcium or placebo pill and 1000 IU/d of calcium. The participants who received the supplementation of vitamin D had a significantly lower risk of ischemic heart disease (13). 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 was 10,899 participants were aged 58 ± 15 years, had a body mass index of 30 ± 8 kg/m2, and 71% of them were female (14). Their serum 25-(OH)D was evaluated at the beginning of the study and five years later. 29.7% of the supplementing participants were of normal levels for vitamin D while the remaining 70.3% were deficient (14). 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. For those who were supplementing had lower risk of or an increase in survival of heart disease (p <0.0001) (14).

From this stand point, supplementation of vitamin D offers a not only prevention for heart disease, but also an increase in survival rate for those heart disease. This could quite be some positive possible signs for vitamin D reversing the affects and consequences of heart disease. More research needs to be conducted on this topic however to fully link the reversal effects of heart disease to vitamin D.

Research over vitamin D is already important in the scope of practice for an RD. The new evidence relating vitamin D and heart disease is just that more important for RD’s to know and understand. This could quite possibly be a turning point in the medical field.

With each study that is done over this subject, vitamin D may be a possible prevention of heart disease.