Phosholipids methylation and brain volume

Dr. Richard Deth wrote in his book “Molecular Origins of Human Attention”:

“The main effect of adding one or more methyl groups to PE (phosphatidylethanolamine) is that the phospholipid molecules cannot pack as close to one another as before, resulting in a loosening of the membrane structure or an increased membrane fluidity.

Under this condition the fatty acids that make up the membrane core have more space available to them so they can flex more easily instead of being tightly constrained.

The activity of receptors and other membrane proteins can be affected by increased membrane fluidity, especially if they exhibit large conformational movements that impinge on the protein/phospholipid interface.

An increase in phospholipid methylation therefore causes a change in the packing density of the cell membrane that can affect the activity of membrane proteins.” (R1)

I wonder if that change can actually shrink / expand the cell - e.g. when methylation of PE is reduced, the molecules are closer to each other and if there is a limited number of them, it should theoretically shrink the membrane, causing shrinkage of the cell.

Does it makes sense?

Once I got this idea, I searched for evidence. Here is something relevant:

“The decrease in brain volume was greater among those with lower vitamin B(12) and holoTC levels and higher plasma tHcy and MMA levels at baseline.” (R2)