Vitamin D is Great for Any Time in Your Life!

Health Effects of Vitamin D

What exactly is vitamin D, and what role does it play in the body? Vitamin D is an essential nutrient crucial for overall health. It facilitates the absorption of calcium, a vital component for maintaining strong bones. Working in tandem with calcium, vitamin D serves as a protective shield against osteoporosis, a condition characterized by bone thinning and increased susceptibility to fractures. Beyond bone health, vitamin D serves various other functions in the body. It supports muscle function, enabling smooth movement, and aids nerve transmission, facilitating communication between the brain and body. Additionally, vitamin D is indispensable for bolstering the immune system, empowering it to fend off harmful bacteria and viruses. 

Vitamin D is naturally present in very few foods, with fortified options being the primary source in the diets of individuals in the United States. Checking the Nutrition Facts label can reveal the vitamin D content of various food and beverage items. For instance, nearly all milk in the U.S. is fortified with approximately 3 mcg (120 IU) of vitamin D per cup. While plant-based alternatives like soy, almond, and oat milk are often fortified, dairy-derived products such as cheese and ice cream typically lack added vitamin D. Additionally, many breakfast cereals, some brands of orange juice, yogurt, margarine, and other food items are enriched with vitamin D.  

Fatty fish like trout, salmon, tuna, and mackerel, as well as fish liver oils, rank among the richest natural sources of vitamin D. Beef liver, egg yolks, and cheese contain smaller amounts of this essential nutrient. Moreover, certain mushrooms are modest sources of vitamin D, with some varieties being exposed to ultraviolet light to boost their vitamin D content.  

Can I get vitamin D from the sun?

Your body synthesizes vitamin D when your exposed skin is in direct contact with sunlight. This natural process provides most individuals with a portion of their vitamin D intake. However, factors such as cloud cover, air pollution, advancing age, and darker skin pigmentation can diminish the amount of vitamin D produced by your skin. Notably, sunlight exposure through windows does not stimulate vitamin D synthesis. It’s essential to be cautious of excessive sun exposure, as ultraviolet radiation poses a risk of skin cancer. Thus, limiting sun exposure is prudent, and when spending prolonged periods outdoors, it’s advisable to apply sunscreen with a sun protection factor (SPF) of 15 or higher. While sunscreen can reduce vitamin D production, it’s still recommended for skin protection. 

Vitamin D supplements are available in various forms, commonly included in multivitamin/mineral supplements or as standalone vitamin D formulations. These supplements typically contain either vitamin D2 (ergocalciferol) or vitamin D3 (cholecalciferol), both of which effectively increase vitamin D levels in the bloodstream. However, research suggests that vitamin D3 may have a more significant and longer-lasting impact on vitamin D levels compared to vitamin D2. Since vitamin D is fat-soluble, it’s advisable to consume supplements with a meal or snack containing some fat to enhance absorption. 

Am I getting enough vitamin D?
Given that vitamin D can be obtained from various sources including food, sunlight, and supplements, a blood test measuring the level of vitamin D in your bloodstream is a reliable method to assess your vitamin D status. The test typically measures a form of vitamin D called 25-hydroxyvitamin D, expressed in either nanomoles per liter (nmol/L) or nanograms per milliliter (ng/mL). To provide context, one nmol/L equals 0.4 ng/mL. For instance, 50 nmol/L is equivalent to 20 ng/mL.

In the United States, most individuals maintain adequate levels of vitamin D in their blood. However, approximately one in four people have insufficient vitamin D levels, which can negatively impact bone health and overall well-being. Certain groups are at a higher risk of vitamin D deficiency: 

  1. Breastfed infants: Breast milk alone lacks sufficient vitamin D, necessitating a daily supplement of 10 mcg (400 IU) for breastfed infants.
  2. Older adults: Aging reduces the skin’s ability to synthesize vitamin D upon sunlight exposure.
  3. Individuals with limited sunlight exposure, either due to lifestyle factors or covering their skin, and the use of sunscreen further diminishes vitamin D production.
  4. People with darker skin tones: Darker skin synthesizes less vitamin D when exposed to sunlight.
  5. Individuals with conditions affecting fat absorption, such as Crohn’s disease, celiac disease, or ulcerative colitis, may struggle to absorb dietary vitamin D.
  6. Those with obesity or who have undergone gastric bypass surgery may require higher vitamin D intake to maintain adequate levels. 

What are some effects of vitamin D on health?

Scientists have long been studying vitamin D to better understand how it affects an individual’s health. Here are a number examples of what this research has shown.

Bone health and osteoporosis
Prolonged deficiencies in vitamin D and calcium can result in weakened bones that are more susceptible to fractures, a condition known as osteoporosis. This ailment affects millions of elderly individuals, predisposing them to fractures and other complications. Muscles play a crucial role in bone health by supporting balance and preventing falls. Inadequate vitamin D levels may contribute to muscle weakness and discomfort. Consuming adequate amounts of vitamin D and calcium through diet, supplemented if necessary, is essential for maintaining bone health and preventing osteoporosis. While vitamin D and calcium supplements can marginally enhance bone strength in older adults, their effectiveness in reducing the risk of falls or fractures remains uncertain. However, ensuring sufficient intake of these nutrients is still crucial for overall bone health and well-being.

Research findings regarding the impact of vitamin D on cancer risk are inconclusive. While vitamin D does not appear to significantly reduce the risk of breast, colon, rectal, or lung cancer, its effect on prostate cancer risk or survival remains uncertain. Elevated blood levels of vitamin D may even pose a potential risk for pancreatic cancer. Clinical trials suggest that vitamin D supplements, with or without calcium, may have a minor effect on reducing the risk of cancer-related mortality, but further research is necessary to fully comprehend the role of vitamin D in cancer prevention and its impact on cancer-related mortality.

Heart disease
Vitamin D plays a crucial role in maintaining cardiovascular health, including the health of the heart, blood vessels, and blood pressure regulation. While some research suggests that vitamin D supplements may help lower blood cholesterol levels and high blood pressure, both significant risk factors for heart disease, other studies yield inconclusive results. Interestingly, in individuals with overweight or obesity, vitamin D supplementation exceeding 20 mcg (800 IU) per day, combined with calcium, may lead to increased blood pressure. Overall, despite potential benefits in certain areas, clinical trials indicate that vitamin D supplementation does not reduce the risk of heart disease development or mortality, even in individuals with low blood levels of the vitamin.

Vitamin D plays a vital role in supporting proper brain function. While some research has suggested a correlation between low levels of vitamin D in the blood and a heightened risk of depression, clinical trials have not demonstrated that taking vitamin D supplements can prevent or alleviate symptoms of depression.

Multiple sclerosis
Individuals residing near the equator often experience increased sun exposure, resulting in higher levels of vitamin D. Interestingly, they also exhibit a lower incidence of multiple sclerosis (MS), a condition impacting the nerves responsible for transmitting messages from the brain throughout the body. Numerous studies have identified an association between low blood levels of vitamin D and the likelihood of developing MS. However, there hasn’t been direct research to ascertain whether vitamin D supplements can effectively prevent MS. Clinical trials involving individuals diagnosed with MS have shown that taking vitamin D supplements does not prevent symptom exacerbation or recurrence.

Type 2 diabetes
Vitamin D plays a role in regulating blood sugar levels, yet findings from clinical trials involving individuals with and without diabetes indicate that supplemental vitamin D does not enhance blood sugar levels, insulin resistance, or hemoglobin A1c levels, which represent the average blood sugar level over the preceding three months. Furthermore, studies suggest that vitamin D supplements do not prevent the progression from prediabetes to diabetes in most individuals. Regarding weight management, neither taking vitamin D supplements nor consuming foods rich in vitamin D has been shown to facilitate weight loss. 

Vitamin D and Healthy eating
As per the federal government’s Dietary Guidelines for Americans, it is recommended that individuals obtain the majority of their nutrients from food and beverages. Foods inherently provide essential vitamins, minerals, dietary fiber, and various other beneficial components crucial for maintaining health. However, fortified foods and dietary supplements may serve as viable options in situations where it is challenging to meet specific nutrient requirements, particularly during certain life stages such as pregnancy.