Maybe people are more indoor-staying nowadays. I have also read articles confirming this fact, see Wahl, D. et al. (2012) A global representation of vitamin D status in healthy populations. Arch. Osteoporos, 7:155-172. They conclude lower levels of Vitamin D in population from the Mediterranean area compared to Northern Europe and North America. Dark tanned skin will less efficiently produce Vitamin D from sun, so even if there is much sun available the production of Vitamin D is less if your skin is darker compared to a person with lighter skin.

Several recent studies have reported that the prevalence of vitamin D deficiency is increasing and has spread across distinct age groups and global regions to reach epidemic proportions. Several risk factors for this deficiency, mainly inadequate sunlight exposure, have been identified. An important recent observation is that low dietary calcium intake may increase turnover of vitamin D metabolites, thereby aggravating vitamin D deficiency.

Vitamin D and calcium are closely related. There can't be adequate levels of one but there aren't any of the other and vice versa. We'd have which is more important.

Air conditioning , too many clothes and everyone I test in ARUBA (12 degrees North of the Equator) is deficient. When I supplement boron to my patients, vitamin D rise without direct suplementation. Boron has disapeared from our food along with many other micr- nutrients

In large part it is factitious due to the use of the wrong evaluation test. 25 OH D is an inactive intermediate. It's interpretation is open to question with many confounders and acceptance of the tests rely on correlative studies which, by definition, cannot show causality. To assess true deficiency the 1,25 di hydroxy D, the active metabolite, must be measured. Additionally there is a misconception about the clinical consequences of D deficiency. That is osteomalacia (not osteoporosis) or rickets in children. Additionally, vitamin D metabolism is much more closely related to phosphate metabolic pathways. Calcium is an indirect regulator of D metabolism. Vitamin D metabolism is fairly complex and poorly understood by most practitioners without special training in mineral metabolism.

Vitamin D deficiency can occur for a number of reasons:

1. The recommended levels of the vitamin are not consumed over the time: This is likely if persons are following a strict vegetarian diet, because most of the natural sources of vitamin D are animal-based, including fish and fish oils, egg yolks, fortified milk, beef liver.

2. Limited exposure to sunlight:Because the body makes vitamin D when your skin is exposed to sunlight, you may be at risk of deficiency if you are homebound, live in northern latitudes, wear long robes or head coverings for religious reasons, or have an occupation that prevents sun exposure.

3. Dark skin:The pigment melanin reduces the skin's ability to make vitamin D in response to sunlight exposure. Some studies show that older adults with darker skin are at high risk of vitamin D deficiency.

4. Over weight and obesity: Vitamin D is extracted from the blood by fat cells, altering its release into the circulation. People with a body mass index of 30 or greater often have low blood levels of vitamin D.

5. Kidneys trouble: the kidneys cannot convert vitamin D to its active form, especially with old age. As people age, their kidneys are less able to convert vitamin D to its active form, thus increasing their risk of vitamin D deficiency.

6. Digestive tract trouble: The digestive system cannot adequately absorb vitamin D. Certain medical problems like Crohn’s disease, cystic fibrosis and celiac disease can affect the ability of the intestine to absorb vitamin D from the ingested food

What were the symptoms of those people in the Canary Islands who presented with Vitamin D Deficiency?

Dennis

Dennis Mazur

Thank you very much to everyone for participating in this debate. The subject is interesting and not very well studied. Now I'm on my way back but when I return I promise to read all the comments in great detail.

Thanks

Felipe Hernández Luis

I agree with Lamia Al-Naama

Thanks

Modern life style and bad nutrition, particularly refined and canned food, race to become zero size and thus decreasing the basic bone minerals and putting pressure on ca+Vit-D. Also, some deficiency of enzymes and kidney problems particularly using Ghee as a cheap source of Fat/lipid for cooking. Ghee is rich in trans fat and nickle. Nickle is very toxic to the kidney and liver, thus the reason of increase in pathologies of these two organs. The situation is pretty bad in Pakistan and India.

Thank you for your answer. I didn't know what the Ghee was. In the Canary Islands, as in the rest of Spain and other Mediterranean countries, olive oil is increasingly used in all its variants (virgin, refined, etc.). According to nutritionists it is the best fat for cooking and dressing salads. Outside Spain, France, Italy, Greece, etc., it is a very expensive product! It is not toxic to the kidneys or liver.

Felipe

Vitamin D deficiency occurs when a person either does not consume enough vitamin D or when their body cannot absorb and metabolize the vitamin D they do consume.

Below are some of the factors that affect whether or not a person is at risk of having a deficiency:

• Living at a high latitude: This is due to there being less access to the sun's ultraviolet-B (UVB) rays.
• Being indoors too much: Spending little or no time outside means missing out on the sun's rays.
• Living in a highly polluted area: Pollution can absorb some of the sun's rays, so reducing scope to make vitamin D.
• Using large quantities of sunscreen: Using enough sunscreen to block UV rays might inhibit vitamin D absorption. But few people use enough sunscreen to block UV rays fully.
• Having darker skin: People with darker skin need more sunlight exposure to absorb enough vitamin D.
• Ambient temperature: Warm skin is better at absorbing the sun's rays to produce vitamin D than cool or cold skin.
• Diet: Eating foods rich in vitamin D, or foods that have been fortified with the vitamin, reduces the risk of vitamin D deficiency.
• Being overweight: Research suggests that being overweight correlates with lower vitamin D levels. This may be because excess body fat somehow affects vitamin D absorption.
• Age: People's ability to absorb vitamin D may decline with increasing age.
• Gut health: Disorders that affect the gut, such as Crohn's disease, can undermine the intestines' ability to absorb vitamin D.
• Kidney and liver health: People with liver or kidney disease tend to have lower vitamin D levels.
• Pregnancy or breast-feeding: The nutritional demands of an infant or fetus may lower vitamin D levels, particularly in women already at risk of vitamin D deficiency.
• Being a breast-feeding infant: Human milk is low in vitamin D. Infants who are nursing may need a vitamin D supplement, particularly if they do not go outdoors everyday.

Vanaspati ghee or Margarine, a fully or partially hydrogenated vegetable cooking oil, often used as a cheaper substitute for ghee and butter and full of trans fat and nickle.Nickle is used as a catalyst to make vanaspati Ghee.

Vanaspati is also an Indian/South Asian slang for Vanaspati ghee or Margarine. In India, vanaspati ghee is usually made from palm oil. Hydrogenation is performed using a catalyst known as "supported nickel catalyst", in reactors at low-medium pressure (3-10 bar). Vanaspati ghee is very high in trans fats, which may compose up to 50% of Vanaspati.

I agree with Entedhar Sarhat

Recommend the following papers:

Article Vitamin D Deficiency: This clandestine endemic disease is ve...

Article Vitamin D deficiency

https://www.medicalnewstoday.com/articles/318060.php

Avoiding exposure to sun

less food containig vit. D intake

old age

kidney diseases

liver diseases

gut health

dark skin

gender

In my opinion , the cause of this deficiency in vitamin D is related with the malnutrition, exposing to the sunshine is not the only source of vitamin D.

A great proportion of these people are intolerant to gluten (celiacs) without confirming their diagnosis. Starting a gluten-free diet may be beneficious for them

Vitamin D3 seemed to decrease mortality in elderly people living independently or in institutional care. Vitamin D2, alfacalcidol and calcitriol had no statistically significant beneficial effects on mortality. Vitamin D3 combined with calcium increased nephrolithiasis. Both alfacalcidol and calcitriol increased hypercalcaemia. Because of risks of attrition bias originating from substantial dropout of participants and of outcome reporting bias due to a number of trials not reporting on mortality, as well as a number of other weaknesses in our evidence, further placebo-controlled randomised trials seem warranted.

To normalize the serum levels of vitamin D certainly is very important in different aspects

I agree with Luis Rodrigo. I think dysbiosis and inflammation are big factors.

Article Inflammation and vitamin D: the infection connection

I feel before we start dissecting the causes of vitamin D deficiency, it is pertinent to understand the kind if data with its strengths & weaknesses be seen first. Almost all shared causes have been attributed or linked/associated with this deficiency. So that aspect is pretty much covered. Now the question should focus on type of subjects included or excluded from the study, sample size, study grade & strength, have the findings been replicated, were there confounders like people with metabolic diseases. So a well-controlled trial with possible exclusion of all contributors need to be planned to see what & how much & possibly how the deficiency(if it is well evaluated by a quality lab test) needs to be do to confirm & understand this. These days every second of third person has insufficient or deficient vitamin D deficiency. Such a study will help many questions apart from this one.

Regards

Intestinal malabsorption of vit. D is a comon event

If the diet in the Canary Island has become more processed, then malabsorption may explain this finding. Processed foods contain emulsifiers that disrupt the microbiome which defends the epithelial barrier. Leaky gut?

In sunny countries the main reason for vitamin D deficiency is to little sun exposure. The attribution of food is less than 1/4 of the vitamin D need. Too little exposure could be for several reasons:

- Working inside all day long

- Being outside only in early morning or late afternoon:especially the hours between 10 and 16 should be used for at least 1/2 hour exposure.

- Extensive covering one self with clothing when outdoors

See for example the paper of Sowah et al.

BMC Public Health (2017) 17: 519

DOI 10.1186/s12889-017-4436-z

If one does not want to expose oneself (moderate ) to the sun, the only real alternative is the use of vit D supplements.

Thaks by commentaries.

Intestinal malabsorption may be a common cause