This article is reviewed, corrected, and approved by: Julia Weiss CNP| RN | MPH

Body aches, tiredness, brain fog, and a bad mood may have an explanation. Vitamin D and B12 deficiency can affect each and every part of our body. It can create unpleasant and painful symptoms, which may lead to you some serious health problems.

The body uses different nutrients. Children and adults worldwide suffer from nutritional deficiencies. Health problems can result when one nutrient affects the absorption of another.

Vitamin D and B12 deficiency together are examples of this. Experts say low vitamin D levels can affect vitamin B12 absorption. Minor genetic errors may prevent your body from getting enough vitamins and minerals despite eating healthy and getting enough sun exposure.

As a result, you may face some kind of health issues. Suppose anyone faces this situation; what should anyone do? Should we increase taking vitamin D or vitamin B2?

Or should we take a greater amount of vitamin D and b12 together? Feeling confused, right? To evade all your confusion here, I am going to delve into the reasons for vitamin D and b12 deficiency together.

Reasons For Vitamin D and B12 Deficiencies Together

There are several reasons for vitamin b12 and vitamin D deficiency.

Reasons for Vitamin D insufficiency

Restricted From Sun Exposure

Sunlight produces vitamin D. Residents of northern areas with limited sun exposure are more likely to be deficient.


Melanin inhibits the synthesis of Vitamin D. Melanin is a pigment found in dark skin.


Having clothing that covers most of the skin lowers your exposure to sunlight, contributing to deficiency.


Diet alone is not always sufficient to obtain enough vitamin D.

Reasons for Vitamin B12 insufficiency:


Vegans may not get enough vitamin B12 because it is mostly found in animal-derived foods.

Absorption issues

Many people have trouble absorbing vitamin B12 because of illnesses, especially if they have pernicious anemia or gastrointestinal surgery.


Older people can have a difficult time in the process of immersing in vitamin B12.

Vitamin B-12 And Vitamin D Deficiency Signs

Knowing your symptoms may help you determine whether you are lacking in one of these vitamins. Vitamin B12 and D deficiency symptoms include:

Vitamin D

Vitamin D deficiency is written on a yellow sticky note. Credits: ReviewsFellas©
  • Bone pain
  • Brain fog
  • Feeling foggy
  • Muscle aches or pains
  • Fatigue
  • Mood changes

Vitamin B12

Vitamin B12 is written on a slate. Credits: ReviewsFellas©
  • Feeling dizzy or breathless
  • Brain fog
  • Pale or jaundiced skin
  • Weakness or fatigue
  • Pins and needles sensation (pinprick sensation)
  • Mouth ulcers
  • Mood changes

Signs Of D3 And B12 Deficiencies Together

A woman keeping her head on a table due to fatigue. Credits: ReviewsFellas©

These are some common signs of vitamin b12 and vitamin D deficiency

  • Imbalance in hormones
  • Create a low immune system
  • Tiredness, dizziness
  • Fatigue
  • Joint pain
  • Osteoporosis
  • Muscle weaknesses
  • Body pain
  • Brittle nails,
  • Memory loss
  • Brain fog
  • Mood disorders
  • Vision problem
  • Itchy hands and feet
  • Depression
  • Infertility issues for both men and women

Prevention Ways You Need to Follow

An assortment of different nutritional diets to boost vitamin B and D12. Credits: ReviewsFellas©

If you are observing these signs, you should contact your doctor as early as possible. Once you get to aware of how much D3 or B12 vitamin you need, you can take precise and necessary steps.

You can usually overcome these deficiencies by modifying your diet and using good nutrition supplements; there are lots of vitamin b12 gummies available on the market.

But for more complicated cases, medicines may be needed.

Diet for The Vitamin B12 Deficiency

Food sources for vitamin B12

  • Fish like tuna, sardines, and salmon
  • Beef liver
  • Turkey
  • Eggs
  • Clams
  • Milk
  • Fortified nutritional yeast
  • Fortified breakfast cereals

Red meat, fish, clams, eggs, and clam juice can help you maintain normal B12 levels. Vegetarians should take milk, nori, shitake mushrooms, and nutritional yeast. The vegan diet can be supplemented with fortified foods.

Diet for The Vitamin D3 deficiency

Food resources for vitamin D

  • Oil, such as Cod liver
  • Fish, Such as trout, salmon, sardines, and tuna
  • Beef
  • Chicken breast
  • Mushrooms
  • Fortified eggs
  • Fortified milk

You can boost your D3 concentration by soaking in the sun every day. It's free. You can include fish oil, egg yolk, fatty fish, and beef liver in your diet. Vegetarians and vegans can get D3 from supplements or fortified foods.

Meeting Vitamin B12 And Vitamin D Requirements

According to age and gender, there is a chart where you can find the daily requirements of vitamin B12 and vitamin D. I put that chart below for my readers.

Vitamin D Requirements


Male (in mcg)

Female (in mcg)

0-12 months



1-70 years



70 years and up



Vitamin B12 Requirements


Male (in mcg)

Female (in mcg)

7-12 months



1-3 years



4-8 years



9-13 years



14 years and up



Importance Of Vitamin D And Vitamin B12

Vitamin D, the sunshine vitamin, is fat-soluble. When the skin absorbs UV rays from the sunlight, our skin absorbs most of the vitamin D.

There are usually two states of vitamin D. Vitamin D3 and vitamin D2, which are available in many food forms.

And if you want to know the source of B12, then B12 is a vitamin that can be mixed with water easily. And you can easily get this vitamin from many supplements, food, fruits, and cereals.

Let's see why we need these two vitamins.

Importance of Vitamin D

  • It helps in better calcium absorption.
  • Works best for bone and muscle health.
  • Reduces osteoporosis risk.
  • For those who have swelling or burning sensation, it can help to minimize the inflammation.
  • It can be helpful in improving cellular growth.
  • Mandatory for healthy teeth and oral health.
  • Boosts immunity.

Importance Of Vitamin B12

For the smooth operation of the nervous system, vitamin B12 is crucial.

  • Supports the construction of Red Blood Cells.
  • Helps in producing an amino acid that supports metabolism.
  • Reduce mood disorder and depression.
  • Supports brain health of the fetuses.


15% of people do not get enough B12. It is found that those people are most vegans and vegetarians or over 50. As one of the eight B vitamins, vitamin B-12 helps the body transform food into glucose, which provides you with energy immediately.

On the other side, approximately 70% to 80% of people lack vitamin D. Vitamin D plays a vital and integral part in boosting energy levels. If you don’t work on your vitamin D level, your immunity will be simulated soon.

You will face problems in doing daily activities. A lack of vitamin D directly affects the stamina of your body as your cells cannot produce energy. In my personal experience, I suggest you take vitamin D gummies, especially in the winter season when you are not getting enough sunlight.

I personally take these gummies and also provide vitamin D gummies for kids, as children can easily get affected by low vitamin D. Vitamin D and B-12 are both different.

You can not get these vitamins like other vitamins and minerals. Only certain foods and natural sunlight provide these vitamins. So it could be a serious health issue if you have Vitamin B12 and Vitamin D deficiency together.

Frequently Asked Questions (FAQs)

Question 1- Can vitamin d deficiency cause weight gain?

Answer 1- Vitamin D deficiency can cause unwanted weight gain. Low vitamin D levels were associated with weight gain in women over 65. The connection between vitamin D deficiency and obesity was similar across many studies.

Question 2- Is Vitamin D Deficiency Genetic?

Answer 2- Around 80% of vitamin D levels are genetic, compared to 25% from diet and environment. Genetic elements can sometimes affect vitamin D levels.

Question 3- Does iron and vitamin D deficiency interrelated?

Answer 3- Iron absorption requires vitamin D. Low vitamin D levels may indicate iron deficiency. To identify the root cause, it is essential to monitor your iron and vitamin D levels and symptoms.

Question 4: Does low vitamin D affect your hair?

Answer 4: Hair may be affected when the body lacks of enough vitamin D. Even hair loss is connected to vitamin D deficiency. Sometimes it can create problems like alopecia areata.

Question 5- Which vitamin deficiency causes white spots on the skin?

Answer 5- Vitamin D, calcium, and vitamin E deficiencies can cause white patches on the skin. These white spots demonstrate that you need to eat a more healthy, balanced diet.

Question 6: Does vitamin b12 increase iron levels?

Answer 6: Your body relies on certain essential nutrients to function properly, such as vitamin B-12, folate, and iron. Indirectly, vitamin B-12 maintains a healthy blood iron level.