Homocysteine, vitamin B and me

About eight years ago I examined the evidence (in recent articles at a level I could understand) that high levels of homocysteine (>15 micromole/L and the threshold is about 10-11) were  linked with cognitive decline in the elderly and that supplements of B6, B12 and folate (folic acid) could slow the decline.  So at that time, I searched out B supplements that were close to those used in the studies, but that wasn't easy since the studies were sort of all over the map. But I did find a brand by Country Life (Basic B Caps) that I liked and which didn't seem to upset my stomach. I had no testing to show my homocysteine levels were high, but the articles I read reported that it was elevated in the elderly.  The studies in the U.S. are different than those in other countries because since the 1960s by law our food is fortified with folic acid, so this affects how useful additional supplements would be late in life.

Recently I have reexamined the issue of high levels of homocysteine and health problems in the elderly, including cognitive decline, cardiovascular events, atherosclerosis and strokes.

I'm a librarian, so my article of choice is always begin with a review article, and I've found several that update what I'd read eight years ago. Review articles have extensive bibliographies which saves time in wandering around the internet. I also always look for full text, and sometimes only the abstract is at the journal site, but may be somewhere else, like Research Gate.

The issues of heart disease and stroke still seem to be unclear, but homocysteine's affect on the brain seems more clear--it damages it--cognitive decline, white matter damage, brain atrophy, neurofibrillary tangles and dementia. Some studies suggest the jury is still out on whether high homocysteine is a marker or a cause, but whichever, supplements of vitamin B are slowing down the damage.

In Sweden, all patients with memory problems are routinely screened for high levels of homocysteine and if they show elevated concentrations, B vitamin supplements are recommended. The Smith/Refsum article concludes that 17 million people (30%)  in the U.S older than 60 could benefit from lowering their homocysteine levels.

"Homocysteine, B vitamins, and cognitive impairment," David Smith and Helga Refsum, Annual Review of Nutrition, 2016, 36:211-239. This includes and additional 15 pages of supplemental material https://www.researchgate.net/publication/305418844_Homocysteine_B_Vitamins_and_Cognitive_Impairment

"The controversial role of homocysteine in neurology: from labs to clinical practice," Rita Moretti and Paola Caruso, International Journal of Molecular Sciences, 2019, 20, 231. https://www.mdpi.com/1422-0067/20/1/231

Both articles suggest further research.  Meanwhile, I'll stay with the B vitamins, but will try to get more naturally through leafy green vegetables (Romaine lettuce, asparagus, broccoli, kale, spinach) for folate B9  https://www.myfooddata.com/articles/foods-high-in-folate-vitamin-B9.php  which may act differently than folic acid (disagreement on this) which is what most supplements have, and B12 (meat, fish, dairy--beef, chicken, pork, lots of cheeses, tuna, salmon ) https://www.goodhousekeeping.com/health/diet-nutrition/g1967/vitamin-b12-super-foods-47012607/   https://www.myfooddata.com/articles/foods-high-in-vitamin-B12.php#vitamin-b12-requirements and B6 (turkey, beef, Tuna, sweet potatoes, potatoes) http://www.whfoods.com/genpage.php?tname=nutrient&dbid=108

Gene mutations that affect homocysteine are very rare.  https://www.skepticalraptor.com/skepticalraptorblog.php/mthfr-gene-vaccines-facts-myths/

"5,10‐Methylenetetrahydrofolate reductase 677C→T and 1298A→C mutations are genetic determinants of elevated homocysteine,"  R. Castro, QJM: An International Journal of Medicine, Volume 96, Issue 4, 1 April 2003.