The Effects Of Good Bone Nutrition On Heart Health

How are they even interlinked?

It’s interesting to see how nutrients that have traditionally been considered as nutrients for bone health can actually have a significant impact on heart health.

People who are at risk of osteoporosis are given a common list of ingredients to add to their diet, including nutrients such as calcium, Vitamin D3 and Vitamin K2.

We cannot have calcium without magnesium.

It’s better off to include magnesium with calcium, though. Both of them are found in bone mineral, though calcium does take up a larger proportion by weight than magnesium in our bone. Two important reasons stand out:

1. A calcium to magnesium intake ratio of more than 2:1 (mass:mass ratio) can be problematic when it comes to issues associated with metabolic, inflammatory and cardiovascular disorders, so if we were to increase our intake of calcium and disregard magnesium… that might be problematic.

2. Calcium and magnesium function in tandem. Calcium provides signals for muscle contraction, while magnesium provides signals for muscle relaxation. Frequent muscle cramps in the middle of the night may signify a lack of magnesium in the diet - or rather, an imbalanced consumption ratio of magnesium to calcium. When that imbalance is chronic and we do go experience muscle issues, can we say that there will be no issues with the heart, even though it contains major muscle groups that are essential for supporting human life? The heart muscles have to keep on contracting and relaxing to pump blood throughout our body when we are asleep.

Therefore, calcium and magnesium are as essential for heart health as they are for providing bone mass and structure.

However, we cannot just assume that the calcium and magnesium that we consume in our diets will automatically be absorbed from our food into our blood, transported throughout the blood, and directed into the bones. There are various checkpoints along the way that are regulated by other nutrients.

What does Vitamin D3 do?

Vitamin D3 is necessary for supporting calcium absorption. As it is mentioned by the National Institutes of Health,

The body needs vitamin D to absorb calcium. Without enough vitamin D, one can’t form enough of the hormone calcitriol (known as the “active vitamin D”). This in turn leads to insufficient calcium absorption from the diet.

In addition, the Cleveland Heart Lab also mentions that

Vitamin D may help by improving the lining of blood vessel walls to allow blood to flow freely and by reducing the harmful effects of inflammation, along with several other effects.

There may be cardiovascular effects that Vitamin D exerts on our arteries, but at the same time, the evidence is inconclusive. Vitamin D alone may not be sufficient for preventing heart disease, though Hopkins Medicine does suggest that

A growing number of studies point to vitamin D deficiency as a risk factor for heart attacks, congestive heart failure, peripheral arterial disease (PAD), strokes, and the conditions associated with cardiovascular disease, such as high blood pressure and diabetes.

Now, how about Vitamin K2?

The funny thing about Vitamin K2 in the arena of bone health is that when it is doing its job correctly, it would also be indirectly supporting heart health.

There are 2 types of Vitamin K: Vitamin K1 and Vitamin K2. Vitamin K1 is obtained from plants and is required for promoting a speedy clotting response, while Vitamin K2 is obtained from bacterial fermentations and provides signalling to different enzymes with regards to bone health.

(As a side note, because Vitamin K1 supports clotting, doctors would not recommend that their heart disease patients take Vitamin K1 together with blood-thinning medications such as warfarin - they are just going to cancel each other’s effects out.)

But what does Vitamin K2 do?

There are 2 separate activities that we want to focus on.

Firstly, the carboxylation of osteocalcin.

As it is said about Vitamin K2 and osteocalcin:

One of the important vitamin K functions in bone metabolism is the post-translational modification of osteocalcin, i.e., vitamin K is a cofactor of γ-carboxylase, which converts glutamic acid residue (Glu) into γ-carboxyglutamic acid residue (Gla) in osteocalcin molecules. Osteocalcin, found in mineralized tissue,5, 6 contains three Gla residues responsible for the affinity of osteocalcin for bone mineral, such as hydroxyapatite.

In layman terms, Vitamin K2 inevitably activates the osteocalcin peptide (which is produced by osteoblast cells) by directing the γ-carboxylase enzyme to perform carboxylation on osteocalcin. Carboxylated osteocalcin has a stronger affinity for bone mineral and can keep it bound better within the bone than uncarboxylated (or undercarboxylated) osteocalcin.

Secondly, the carboxylation of Matrix GLA Protein (MGP).

The biology of vascular calcification is a rather complex thing to understand:

MGP is a vitamin K-dependent matrix protein expressed by numerous cell types including VSMCs, macrophages, and osteoblasts (Shanahan et al., 1998). MGP was firstly isolated in bone, but it is also found in blood vessels acting as an inhibitor of vascular calcification (Bjorklund et al., 2018), due to its ability to bind to calcium crystals, thus negatively affecting hydroxyapatite mineral formation (O’Young et al., 2011) and to interfere with osteoblastic differentiation of VSMC through inactivation of BMP-2 signaling (Xue et al., 2006). It is important to note that MGP, to be fully active (Gla-MGP), needs to be γ-carboxylated in a vitamin K-dependent manner. However, MGP activity is not only regulated by vitamin K, but also by several other factors such as vitamin D, retinoic acid and extracellular calcium ions (Proudfoot and Shanahan, 2006).

The carboxylation of matrix GLA protein follows the exact same mechanism as the carboxylation of osteocalcin. When all the Glu has been carboxylated into Gla, the protein will also have a higher affinity for mineral calcium.

As we can see, sufficient carboxylation is necessary for the osteocalcin to keep the bone mineral within the bone. MGP, on the other hand, is produced by the vascular smooth muscle cells (VSMCs) that line our arteries, and its carboxylated form binds to any mineral calcium that could otherwise preciptate onto our arterial walls and cause arterial calcification.

We can therefore say that Vitamin K2 provides 1 function (carboxylation) that targets 2 proteins: 1 protein keeps mineral calcium entrapped where it should be (in the bones), while the other protein prevents mineral calcium from depositing where it shouldn’t be (in the arteries).

Therefore, Vitamin K2 would simultaneously affect both heart health and bone health.

Isn’t it interesting how our bones and our heart can be so intertwined?

It’s just a case of biochemistry.

And we can see also that the nutrients required to support healthy bones and healthy hearts do tend to overlap:

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