For those with vitamin D deficiency, especially those suffering from fatigue, pain and immunity problems, it’s really important to get those levels back up to a normal range (>50 nmol/L). However, even when high doses are prescribed, they don't always work. Here are some common reasons why your vitamin D levels may not be increasing.

1. You May Have a Magnesium Deficiency

Magnesium is essential for your body to convert supplemental vitamin D into its active form. Without enough magnesium, even high doses of vitamin D can go to waste. It's a good idea to get a magnesium blood test from your GP or a specialist clinic.

• Product Suggestion: AltruVita Magnesium 100% contains a high-absorbing form of magnesium.

2. You Aren't Taking Your Supplement with Fat/Oil

Vitamin D is a fat-soluble vitamin and needs to be taken with a fat-containing meal or snack to be absorbed properly. If you only take your supplements with water, most of the vitamin D cannot be absorbed into your body. To ensure it absorbs well, take your supplement with a meal every day.

3. You Are Missing Doses

Consistency is key. If you only take your prescribed dose half the time, it will naturally take twice as long for your levels to increase. To stay on track, set reminders to take your specific doses on time.

4. You Have had Intestinal Surgery? 

Removing the sites for vitamin D absorption (ileum, jejunum and colon) can make it difficult to absorb your supplements. If you had intestinal surgery or bariatric surgery, check what parts have been removed, as although the remaining intestines adapt a little, you may actually need intramuscular vitamin D injections going forward. 

5. You Have Underlying Gut Health Issues

Certain intestinal conditions can make it difficult to absorb oral vitamin D supplements.

• Intestinal Diseases: Conditions like Crohn's disease, coeliac disease, and gastrointestinal cancers can hinder the absorption of oral vitamin D supplements. This may be caused by damage to the gut flora or a reduced surface area for absorption.
• Intestinal Surgery: If you've had intestinal or bariatric surgery, the sites for vitamin D absorption (like the ileum and jejunum) may have been removed, making it difficult to absorb supplements.

To support your gut health, AltruVita ProfBiotics Complex+ provides 10 live strains totalling 20 billion bacteria per capsule for £25.46 a month.

6. You're Taking the Wrong Type of Vitamin D

The type of Vitamin D you take matters. Most people will not absorb Vitamin D2 as effectively as Vitamin D3, so it's important to make sure you're taking the correct type.

AltruVita Vitamin D3 1000IU provides a 2-month supply of active natural vitamin D₃ from £8.46.