Low vitamin D and memory problems while having an underactive thyroid
Vitamin D is necessary for brain activity
Vitamin D regulates metabolism of calcium, it reduces inflammation (1–3), and it is quite active in brain areas important for focus and memory (4,5).
Research has shown that the lack of vitamin D in people with an underactive thyroid may lead to memory and focusing problems, which increases the risk of depression and lower day-to-day life quality in people diagnosed with Hashimoto’s (6, 7).
Low vitamin D is considered lower than 50 nmol/L (20 ng/mL) (8).
The most common issues with low vitamin D (9):
Feeling tired all the time
Feeling down or depressed
Muscle or bone pain
Getting sick often (repeated infections)
The most common symptoms of low vitamin D in people with Hashimoto’s are:
Problems with short-term memory
Feeling down or depressed
Low blood levels of vitamin D are often found in people diagnosed with Hashimoto’s (10,11), and can cause problems with focusing and memory, resembling early stages of Alzheimer’s (12).
Vitamin D is important in fighting off inflammation, one of the main reasons for problems with memory and focus. Research has shown that Hashimoto’s patients have an increased level of inflammatory molecules circulating in their bodies and causing inflammation in different parts of the body (13, 14). Vitamin D is known to block these molecules from causing inflammation, but only when vitamin D levels are high enough (15).
Low vitamin D often coexists with higher TSH and TPO levels, as well as higher TG antibodies. Whether low vitamin D causes an increase in TSH remains to be researched, but it shows a connection between vitamin D and TSH (16–20). It’s unknown if low vitamin D levels is a cause or a consequence, because a lot of people diagnosed with Hashimoto’s have other conditions too, and these conditions might affect production or how vitamin D is used in the (by the) body (20).
Making sure your vitamin D levels are in a good range is important the whole year round.
During the summer a part of your vitamin D will come from sunlight-activation in your skin (21), and during the winter you might need to opt to take vitamin D supplements and vitamin D fortified foods to keep your vitamin D levels in a good zone.
What is the recommended daily intake of vitamin D?
The recommended daily intake (RDA) of vitamin D for people between ages 9 and 70 is set at 15 μg/d (600 iu/d) in the USA and 5 μg/d (200 iu/d) in most of Europe (the upper limit is 100 μg/d (4000 iu/d)), and 20 μg/d (800 iu/d) in Germany, Austria, and Switzerland.
Blood levels of vitamin D3 should be above 30 μg/L, while at least 37.5–50.0 μg/d (1500–2000 iu/d) of vitamin D may be the optimal level (22–24).
Vitamin D rich foods
A few foods contain vitamin D: egg yolk, salmon, tuna, mackerel, fish liver oils, as well as beef liver (25, 27). Mushrooms with enhanced levels of vitamin D2 from being exposed to ultraviolet light under controlled conditions are also available. Cooking won’t will not destroy much of the vitamin D content found in food (28).
Ready-to-eat breakfast cereals often contain added vitamin D, as do some brands of orange juice, yogurt, margarine, and other food products.
If milk products are not fortified with vitamin D, they are low in vitamin D — the only exception is butter because it’s high in fat (26).
What are the best vitamin D supplements?
What will determine how good is vitamin D is how well it is absorbed in by the gut.
25-hydroxyvitamin D (25-OHD)-the best form of vitamin D. There are vitamin D drops (in both oil and alcohol) and vitamin D pills, which might be as oil capsules or pills using either cellulose or lactose as a carrier.
According to research oil-based capsules and drops yield the best results and best increase in vitamin D levels (28).
Genetic factors play a role in how well a person is able to absorb and use vitamin D in/from their bloodstream (29, 30).
How long it takes to improve focus and memory problems caused by the low vitamin D levels?
If your vitamin D levels are low, it might take some time to improve them. You can retest yourself after 5–6 weeks of taking vitamin D — at that time you should see improvement in your vitamin D levels ().
Your memory should improve within 6–8 weeks.
How do you know if your vitamin D levels are okay?
The most accurate way to measure how much vitamin D is in your body is the vitamin D blood test.
Super high levels of vitamin D might not help, and might even be counterproductive in a long term.
You can track vitamin D in BOOST Thyroid app.
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