Vitamin D Foods in Perimenopause: Protecting Bones and Beyond
Understand why vitamin D deficiency is common in perimenopause and which foods help. Covers oily fish, eggs, fortified foods, sunlight, D3 vs D2, and pairing with K2 and calcium.
Why Vitamin D Deficiency Is So Common in Perimenopause
Vitamin D deficiency is widespread in the general population, but perimenopausal women face a particular convergence of risk factors. As estrogen declines, the gut's ability to absorb calcium falls, and adequate vitamin D is essential to compensate because it regulates calcium absorption directly. Skin synthesis of vitamin D from sunlight decreases with age because the skin becomes less efficient at converting UVB radiation into the precursor form. Indoor working patterns, use of sunscreen, higher body fat, and living at latitudes above 35 degrees north all further reduce synthesis. Several medications common in midlife, including some statins, antacids, and corticosteroids, also impair vitamin D status. The result is that many perimenopausal women arrive at this hormonally significant period already depleted in a nutrient that is critical for bone preservation, immune function, muscle strength, and mood regulation.
Food Sources of Vitamin D
Very few foods contain substantial amounts of vitamin D naturally, which is one reason deficiency is so common. Oily fish are the best dietary sources: a 100-gram portion of salmon provides 400 to 600 IU, while herring and mackerel provide similar amounts. Canned sardines and tuna offer more modest but still useful contributions and are easier for many women to incorporate regularly. Egg yolks provide 40 to 50 IU each, with hens raised outdoors or fed vitamin-D-enriched feed producing eggs with notably higher levels. Beef liver provides vitamin D alongside vitamin A and B12, making it a nutrient-dense choice. Certain mushrooms, particularly when exposed to UV light or sunlight with their gills facing upward, can produce significant amounts of vitamin D2: some studies show that 30 to 60 minutes of midday sun exposure can generate 400 IU or more per 100-gram serving of mushrooms treated this way.
Fortified Foods and Their Limitations
Many countries have addressed widespread vitamin D insufficiency through food fortification. Fortified foods commonly include cow's milk, plant-based milks such as oat and soy, some breakfast cereals, and certain orange juice brands. The amounts added are typically 80 to 100 IU per serving, which is meaningful as part of a daily total but insufficient on its own given that current recommendations for women in perimenopause often range from 800 to 2,000 IU per day, depending on baseline status and clinical guidance. Reading labels matters because fortification levels vary considerably. Dairy products generally fortify at consistent levels, while plant milks vary widely by brand. Fortified foods also typically use vitamin D2, which is less effective at raising blood 25-hydroxyvitamin D levels than D3.
The Sunlight Reality
For most people, sunlight remains the most efficient route to adequate vitamin D. The challenge is that meaningful synthesis requires UVB radiation, which is blocked by glass, sunscreen, clouds, and atmospheric angle. In the UK, northern Europe, Canada, and the northern US, UVB radiation strong enough to generate vitamin D is only available from roughly April to October, and only during the middle of the day. Exposing arms and legs (not face, to reduce skin cancer risk) for 15 to 30 minutes between 11am and 3pm on sunny days can generate 1,000 to 3,000 IU, far more than any food source. However, many women find this impractical, uncomfortable in hot weather, or counterproductive given concerns about skin health. Supplementation is therefore a practical necessity for most women living above 35 degrees latitude during autumn and winter.
D3 Versus D2, Testing, and Supplementing
Vitamin D3 (cholecalciferol) is the form produced by human skin and found in animal-derived foods. D2 (ergocalciferol) is the plant-derived form produced by fungi and used in some fortified foods and vegan supplements. D3 is consistently more effective at raising and sustaining blood 25-hydroxyvitamin D levels, typically two to three times more potent in raising serum levels compared to equivalent D2 doses. The most reliable way to guide supplementation is to test: a simple serum 25-hydroxyvitamin D test identifies whether you are deficient (below 50 nmol/L), insufficient (50 to 75 nmol/L), or adequate (above 75 nmol/L). Most perimenopause clinicians recommend a target of 80 to 100 nmol/L. Daily doses of 1,000 to 2,000 IU D3 are safe for most women and maintain adequate levels when dietary and sunlight exposure are limited. Doses above 4,000 IU should be guided by testing.
Pairing Vitamin D with K2 and Calcium
Vitamin D increases calcium absorption from the gut, but that calcium needs to reach bones rather than accumulate in soft tissues or arteries. Vitamin K2 (specifically the MK-7 form) activates proteins that direct calcium into bone and away from blood vessels. The combination of vitamin D3 and K2, sometimes referred to as a synergistic pair, is increasingly recommended for perimenopausal bone health. K2 is found in fermented foods, particularly natto (fermented soybeans, very high), fermented cheeses like Gouda and Brie, and some organ meats. Calcium itself works best when spread across the day in amounts of 500 milligrams or less per dose, because absorption efficiency drops sharply with larger single doses. Prioritising calcium-rich foods like dairy, fortified plant milks, canned fish with soft bones, and cooked leafy greens alongside adequate D and K2 gives bones the full picture they need.
Tracking Symptoms While Optimising Vitamin D
Vitamin D's effects on bone density are cumulative and not felt day to day, but its influence on mood, muscle strength, and fatigue can be noticed within weeks of correcting a deficiency. PeriPlan lets you log symptoms and track patterns over time, making it easier to notice whether energy, mood, or joint comfort changes as you address your vitamin D status. Keeping notes on what you are eating and when you are supplementing gives you a clearer record to discuss with a clinician.
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