Vitamin D helps Maintain Strong Bones

The important role of Vitamin D has been one of the many aspects of nutrition that has been uncovered. We know Vitamin D is important in maintaining strong bones and teeth.  Another important role is its role in the function of our intestines.  Drs. J. Hernandez and C. Palacios did a study in South Florida on 213 children predominately Hispanics and some Blacks.  They were studying how a dietary fiber supplement (soluble corn fiber) affects bone mass in children and adolescents.

They first measured the Vitamin D levels of the study children.  Surprisingly in sunny Southern Florida 68% of these children were found to have suboptimal levels of the vitamin.  While Vitamin D can be obtained by mouth in food and pills, most people obtain this vitamin from skin exposure to sunlight.  For youth approaching or experiencing puberty, a period of profound changes in their body is about to occur. This includes rapid changes in bone mass.   It is also known that adolescents tend to eat less than the recommended amounts of Vitamin D.  Vitamin D deficiency could have serious long term health issues.

With such a high percentage of children with low levels of Vitamin D it was a good opportunity to study the influence of low Vitamin D on calcium absorption and the intestinal barrier.  Vitamin D is linked to many different organs by Vitamin D receptors.  These receptors act like docking stations for Vitamin D to bind to and trigger different effects in the skin, intestine, bone, parathyroid gland, immune system and pancreas. 

The effect on the intestine is on the intestinal barrier which is a layered wall that allows the gut to absorb nutrients and keep out harmful bacteria.  This wall is composed of intestinal cells and proteins called tight junctions that act like bricks sealing these cells together.  Tight junctions play an important role in maintaining the structure of the intestine.

Chronic disruption of the gut barrier (leaky gut) is now recognized as a major contributor to various chronic diseases as this disruption can trigger inflammation and affect multiple organ systems.  It is implicated in conditions ranging from autoimmune and metabolic diseases to mental health issues and even aging-related disorders.

Vitamin D receptors in the gut improve calcium absorption and strengthen the intestinal barrier.  Using the soluble corn fiber there was a 12 % increase in the absorption of calcium.  This was also associated with an increase in certain microbiomes.  This increase in calcium absorption has long term health benefits as it will help prevent the development of osteoporosis in later life.

Only a few foods contain Vitamin D, trout, salmon, tuna, egg yolks but many are fortified such as dairy products, plant based milk, cereals, and baby formulas.  The recommended daily amount is 600 IU.  Upper limits are 1000 to 4000 IU.  Focusing on a balanced diet rich in fiber, fruits, vegetables and healthy fats can support intestinal barrier health.

Notice that is the same old thing, a HEALTHY diet---- not processed food!

Published 05/05/2025

by Sally Robinson MD