“Heavenly sunshine” is more than an old gospel song; sunshine is therapeutic, healing, and preventative. The great thing is that, if you walk outdoors, you can get exercise, fresh air, and sunshine all at the same time!

Ten or 15 minutes in noontime summer sun leads to the production of 10,000 IU (International Units) of Vitamin D. “This study adds to existing research that suggests low levels of vitamin D are linked to an increased risk of Type 2 diabetes.”¹

However, we lose the ability to make vitamin D from sunlight as we get older. “There is a wealth of evidence showing that vitamin D is necessary for insulin secretion and can reduce abnormal increases in insulin resistance in humans as well as experimentally. Improving vitamin D status before irreversible defects develop in islet cells, insulin resistance, and related defects also appears to be important.”² Unfortunately, “people over age 50 have an increased risk of vitamin D deficiency and the risk increases with age. As people age they lose some of their ability to synthesize vitamin D from sunlight.”³

A new study warns that people who have low levels of vitamin D are more likely to be obese and more likely to have type 2 diabetes.⁴

Many studies provide evidence that sunshine may help prevent diabetes. “It has been shown that adequate vitamin D levels may help protect against the development of type 1 and type 2 diabetes, although the exact reasons for this are not entirely understood yet. Furthermore, adequate vitamin D intake may help improve glycemic control in patients with diabetes.”⁵

Diabetics may need more sunshine than non-diabetics. During periods of low or no sunlight, diabetics may wish to take a vitamin D3 supplement, being careful not to overdose. Vitamin D3 is frequently combined with vitamin K2 for best efficacy.

Vitamin D

The “sunshine vitamin” appears to form under the skin when sunlight reaches the skin. Most of the nutrient is formed in reaction to sunlight, but you will also find small amounts in foods such as eggs and oily fish. Scientists have discovered a link between vitamin D levels and our ability to deal with glucose. There are vitamin D receptors in almost all the cells in the body, suggesting vitamin D plays a role in most chemical processes; but some more interesting roles of vitamin D include beta cell function and regulation—the cornerstone of diabetes. “Specific receptors in the pancreas may only switch on when sufficient vitamin D is available. The thinking is that vitamin D may support the function of the pancreas.”⁶

Skin synthesis by UVB-irradiation from summer sunshine provides Vitamin D; and, to a small extent, Vitamin D comes from absorption of food. However, because these processes become less efficient with age, many experts suggest that ≥1000–2000 IU [25–50μg] of vitamin D daily is necessary for older people. Some studies suggest that correcting vitamin D deficiency could reduce insulin resistance and improve insulin secretion. Health Canada advises all adults over the age of 50 to take a vitamin D3 supplement of 400 IU each day. We recommend 1000-5000 IU/day for maintenance of adequate vitamin D levels, but consult with your doctor about your vitamin D needs.

You are at greater risk for vitamin D deficiency if you are over 50, obese, diabetic, or vegan. This is because most dietary sources of Vitamin D come from animal-based foods. You can ask your doctor to order a vitamin D blood test. According to my health care provider, the normal range is 20-79 ng/mL.

I spend at least 20 minutes a day in the sunshine, and I take 5,000-10,000 IU of vitamin D3 daily.

Circadian Rhythm

An additional benefit of sunlight is its crucial role in your circadian rhythm. A circadian rhythm is a natural, internal process that regulates the sleep-wake cycle and repeats on each rotation of the earth roughly every 24 hours (Wikipedia). Dr. Arlene Taylor, brain-function specialist, describes it:

“When sunlight enters the eye, it strikes the light-sensitive retina. Remember, the retina is part of the central nervous system (CNS) and is connected to the brain via the optic nerve. The retina contains different types of cells. The photoreceptor cells are sensitive to light. No doubt you’ve heard of rods and cones. These cells are specialized neurons in the human eye. Rods are more sensitive to light and help you see under low-light conditions. They do not process color vision, however. Cones are capable of color vision and are responsible for high spatial acuity. They need more light to produce a correct signal, however, so may find it difficult to process color on a dark night outdoors.

“The photosensitive ganglion cells in the retina, discovered only in the past decade or so, communicate not only with the master circadian pacemaker or clock located in the brain’s hypothalamus (known as the suprachiasmatic nuclei or SCN) but also impact many other brain areas that are known to be involved in the regulation of several functions including your health.”⁷

Adventist Vegetarian Diabetics™ Recommends:

1. Spend 20-30 minutes a day in the sunshine. Even on overcast days, exposing your eyes to daylight helps get and keep your circadian rhythm on track. Jimmy Moore, author and health podcaster, recommends three sessions a day in the sunshine: early morning, mid-day, and late afternoon to establish and maintain your circadian rhythm.
2. Wear sunglasses that block ultraviolet B (UVB) rays (or, if you wear glasses, get progressive lenses that respond to light and dark). Ultraviolet light from the sun may contribute to the development of cataracts. If needed, wear a visor or baseball cap to shield your eyes from direct sunlight.
3. Ask your doctor to run a blood test to determine your vitamin D level. Take a vitamin D3 supplement if you need to, especially if you are over 50.

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¹Dawar, Anil. “Sunshine vitamin can stop diabetes: Boost your health just by going outside,” Express (February 24, 2015). https://www.express.co.uk/life-style/health/560066/Vitamin-D-in-sunshine-can-cut-risk-of-diabetes (accessed on 7/26/2020). (Richard Elliott).

²Boucher, Barbara J. “The Problems of Vitamin D Insufficiency in Older People,” Aging Dis. 2012 Aug; 3(4): 313–329. Published online 2012 Jun 6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3501367/ (accessed on 7/26/2020).

³“Vitamin D Deficiency: A Common Risk Factor for Seniors,” Parent Giving, n.d. https://www.parentgiving.com/elder-care/vitamin-d-deficiency-a-common-risk-factor-for-seniors/ (accessed on 7/26/2020).

⁴Davies, Madlen. “Lack of sunshine increases the risk of diabetes MORE than being obese,” Daily Mail (February 23, 2015). https://www.dailymail.co.uk/health/article-2965410/Lack-sunshine-increases-risk-diabetes-obese-Low-level-vitamin-D-plays-major-role-disease.html (accessed on 7/26/2020).

⁵Muccioli, Maria, PhD. “Vitamin D And Diabetes: What’s The Connection?” Diabetes Daily (January 13, 2020). https://www.diabetesdaily.com/blog/vitamin-d-and-its-role-in-diabetes-402285/ (accessed on 7/26/2020).

⁶Gorin, Amy, RDN; medically reviewed by Lynn Grieger, RDN, CDCES. “What Vitamin D Is Good for When You Have or Are at Risk for Diabetes,” Everyday Health (last updated June 30, 2020). https://www.everydayhealth.com/type-2-diabetes/diet/vitamin-d-deficiency-linked-with-diabetes/ (accessed on 7/26/2020).

⁷Taylor, Arlene R., PhD. “Sunlight & the Retina,” Arlene Taylor’s Blog (October 13, 2020). https://arlenetaylor.blogspot.com/2020/10/sunlight-retina.html (accessed on 10/15/2020).

Additional Information

Sunny Side: Sunlight | NEWSTART Now | Episode 4

CAVEATS:
If you are diabetic/pre-diabetic, SKIP the cashew “ice cream”!
Puree berries of your choice (raspberries, strawberries, blueberries, blackberries) with heavy cream (or unsweetened coconut cream), and nut milk (almond or coconut). Pour into a freezer container, freeze until it becomes the consistency you desire, stir every hour or so.

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More References:

• Sunlight and Diabetes
• Sunlight and Health, General
• Vitamin D