Vitamin D: A stressed person’s guide to crafting a daily vitamin and supplement regimen- Part 3

Author: Audrey Fleck - MS, RDN, LDN Publish Date: March 11, 2024

In the realm of health and wellness, few nutrients have garnered as much attention in recent years as vitamin D. Often referred to as the “sunshine vitamin,” its importance extends far beyond merely supporting bone health. Emerging research has highlighted its crucial role in immune function, mood regulation, and overall well-being. Yet, despite its significance, a large portion of the global population remains deficient in this essential nutrient.

Welcome to part 3 of my series aimed at helping you craft a daily vitamin and supplement regimen for long-term optimal health, which I call your “Foundational Supplement Regimen”. In this installment, we delve into the intricacies of vitamin D supplementation, exploring its benefits, optimal dosage, and considerations for different demographics. Whether you’re seeking to bolster your immune system, improve your mood, or simply optimize your health, understanding the ins and outs of supplementing with vitamin D can be a game-changer on your wellness journey.

Vitamin D

Vitamin D is truly a powerhouse, acting as a hormone that significantly influences our well-being. Think of it as a key player in a complex orchestra, with receptors on every cell in our body. This means Vitamin D has a hand in regulating our mood, supporting the immune system, maintaining a healthy gut lining, and playing a vital role in bone health, among other functions. If you are navigating anxiety and depression, optimizing your Vitamin D levels can be helpful for improving your mood. Moreover, for those focused on mental health, maintaining optimal vitamin D levels has been linked to a reduced risk of Alzheimer’s disease.

Sunlight is our main source for Vitamin D and because of that, we need to discuss why getting enough Vitamin D is a little complicated. Let’s dive into it.

  • Vitamin D is obtained exclusively from UVB rays emitted by the sun.
  • The farther you live from the equator, the less Vitamin D you can generate from sunlight. For instance, those in the Northeast, USA (hello from Pennsylvania!), cannot produce Vitamin D from November to February.
  • Individuals with darker skin need more sun exposure to meet their Vitamin D requirements because melanin (what gives us our skin color) can reduce your body’s ability to make Vitamin D from the sun. The darker our skin, the more melanin we have.
  • Aging may affect the efficiency of converting Vitamin D from UVB rays, with older people potentially less adept than their younger people.
  • Sunscreen, while essential for protecting our skin from harmful UV rays and reducing the risk of skin cancer and premature aging, can impact our vitamin D exposure. Sunscreen blocks UVB rays – the same rays that provide Vitamin D.

Additionally, certain factors contribute to the risk of Vitamin D deficiency

  • Excess body fat: High body fat can impede the circulation of Vitamin D, leading to a higher likelihood of deficiency. Obesity shows a significant correlation with Vitamin D deficiency.
  • Digestive issues: Those with inflammatory bowel disease or digestive problems affecting fat absorption may struggle to obtain Vitamin D from their diet, as it is a fat-soluble vitamin requiring fat for absorption.
  • History of gastric bypass surgery
  • Liver disease
  • Kidney Disease
  • Older age (>65 years)

Get Your Vitamin D Levels Tested

Given the widespread prevalence of Vitamin D deficiency, especially if you fall into the at-risk categories mentioned earlier, it’s crucial to ask your doctor or include it in your annual nutrition check-up with your Registered Dietitian. This proactive approach helps determine the right dosage for your Vitamin D supplementation, eliminating the need for guesswork.

Here’s what you should keep in mind:

  1. Request a 25-OH-D test.
  2. If you have a history of Vitamin D deficiency, check your levels twice a year – once in the fall and once in the spring.
  3. The “normal” range for Vitamin D is broad, ranging from 30-100 ng/mL. However, for optimal health, aim for levels above 60. To maximize the benefits of Vitamin D on bone, metabolism, and muscle, target a level closer to 75, according to the Endocrine Society.
  4. Higher isn’t always better. Overdosing on Vitamin D and having excessively high levels can lead to adverse health outcomes.

Is it possible to obtain sufficient Vitamin D from food alone?

My stance is no. Although certain foods contain Vitamin D, depending solely on them necessitates daily consumption. Examining the list below can give you an idea of how achievable this might be for you. It would entail you eating those foods daily to attain enough through diet alone, a task that, based on my experience with clients, is nearly impossible. As mentioned earlier, sunlight is intended to be our primary source of Vitamin D.

The Recommended Dietary Allowance (RDA) for vitamin D is set at 600 IU daily for adults and 800 IU daily for older adults. These levels are still arguably too low for optimizing Vitamin D levels. Considering the widespread prevalence of Vitamin D deficiency and drawing from my clinical experience, I advocate for supplementation beyond food to meet the body’s needs adequately.

Best Vitamin D Food Sources

  • Fatty Fish:
    • Salmon (3.5 ounces): 360 IU
    • Mackerel (3.5 ounces): 345 IU
    • Sardines (1 can, drained): 165 IU
  • Canned Tuna (3.5 ounces, in water): 154 IU
  • Egg Yolks (1 large egg): 41 IU
  • Beef Liver (3.5 ounces): 49 IU
  • Fortified Foods:
    • Fortified Milk (1 cup): 120 IU
    • Fortified Orange Juice (1 cup): 137 IU

Vitamin D Supplement Tips

Dosage: As a general recommendation, I suggest 1000-2000 IU of Vitamin D3 daily for most individuals. For those at risk of deficiency and aware of suboptimal Vitamin D levels, I may suggest higher doses from fall to spring, typically closer to 4000 IU daily.


  • Taking Vitamin K alongside Vitamin D is crucial, as they synergistically contribute to bone health. Most high quality vitamin D supplements include vitamin K with it.
  • Additionally, magnesium complements Vitamin D. Magnesium plays a role in converting Vitamin D into its active form in the liver, and sufficient Vitamin D levels are necessary for enhancing magnesium absorption.

Putting it All Together: Your Personalized Path to Wellness

Taking daily supplements is a practical step toward a more vibrant, stress-resilient life. Remember, the path to well-being is unique for everyone. If you need advice or personalized recommendations tailored to your individual needs, feel free to reach out—I’m here to assist. Book a free virtual consult for personalized guidance on your wellness journey.

Access Professional-Grade Supplements

Visit my Fullscript Dispensary to explore a selection of my go-to professional-grade supplements. Each product in this dispensary has been handpicked to meet the highest standards of quality, ensuring you have access to supplements that support your well-being.

Remember, wellness is a personal and evolving journey. Together, we can tailor a supplement routine that aligns with your unique needs, helping you achieve your health and wellness goals.


  1. Holick, M. F. (2007). Vitamin D deficiency. New England Journal of Medicine, 357(3), 266-281. doi:10.1056/NEJMra070553
  2. Wacker, M., & Holick, M. F. (2013). Sunlight and Vitamin D: A global perspective for health. Dermato-Endocrinology, 5(1), 51–108. doi:10.4161/derm.24494
  3. Pludowski, P., Holick, M. F., Pilz, S., Wagner, C. L., Hollis, B. W., Grant, W. B., … & Ritz, E. (2013). Vitamin D effects on musculoskeletal health, immunity, autoimmunity, cardiovascular disease, cancer, fertility, pregnancy, dementia and mortality—a review of recent evidence. Autoimmunity reviews, 12(10), 976-989. doi:10.1016/j.autrev.2013.02.004

About the Author

Audrey Fleck - MS, RDN, LDN

I’m Audrey Fleck, a dedicated dietitian with over a decade of experience, and the founder of Functional Origins, my private practice located in Bucks County, PA. With a strong educational background, including a BS in Nutrition and Dietetics and an MS in Human Nutrition and Functional Medicine, I specialize in providing an integrative and functional approach to healing, primarily tailored for women.