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Comment by athenot | Hacker News Reader

> This essential micronutrient is produced mainly by plants, including phytoplankton, bacteria, and fungi; people and animals must acquire it through their food.

Key here is beneficial bacteria and fungi, which a lot of our foods are increasingly poor in.

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Would the washing of all our "anti-bacterial" cleaning products into the oceans and water ways be killing off the invisible foundation of the food chain: Bacteria and Fungi.

Molds (Fungi) and Bacteria are something Humans have been at war against with their cleaning and pesticides for decades...

Phytoplankton eat bacteria, correct?

very interesting idea

I also wonder to what extent thiamine is recycled in nature, apart from thiaminases, if an predator high up the food chain dies and floats/sinks in the sea, will all the accumulated thiamin be recycled? in what pathways is thiamine consumed in say a human? what would increase or decrease the metabolic consumption (not eating) of thiamine?

Wikipedia's Thiamine / antagonists section:

>Thiamine in foods can be degraded in a variety of ways. Sulfites, which are added to foods usually as a preservative,[34] will attack thiamine at the methylene bridge in the structure, cleaving the pyrimidine ring from the thiazole ring.[13] The rate of this reaction is increased under acidic conditions. Thiamine is degraded by thermolabile thiaminases (present in raw fish and shellfish[12]). Some thiaminases are produced by bacteria. Bacterial thiaminases are cell surface enzymes that must dissociate from the membrane before being activated; the dissociation can occur in ruminants under acidotic conditions. Rumen bacteria also reduce sulfate to sulfite, therefore high dietary intakes of sulfate can have thiamine-antagonistic activities.

Is this perhaps due to sulfate pollution (bunker oil?) and acidification of the oceans?

The heavy fuel oil sulfur pollution situation has improved in Europe massively since 2015 when the emissions controls started. By now we should see an effect.

When Indians who follow a strict vegan diet started migrating to the western world, a lot of them would begin to suffer from pernicious amaemia, a disease caused by deficiency of dietary vitamin B12. Similar diseases are present in India but appeared to be less common.

Most published research are rather diplomatic about this phenomenon[0]. However, reading between the lines, the reason appears to be the lack of fecal and insect contamination in food supply, which accidentally eliminated a lot of exogenous micronutrients not present in plants.

[0]:https://www.ncbi.nlm.nih.gov/pubmed/11470726

B12 deficiency doesn't cause pernicious anemia, pernicious anemia is a cause of B12 deficiency, its a GI absorptive disorder (lack if intrinsic factor).

I use the term loosely in reference to all types of anaemia arising from cobalamin deficiency, as the NIH and Mayo clinic do[0][1]. After all, lack of IF is only one of the many causes and the symptoms are similar regardless of aetiology.

[0]:https://www.mayoclinic.org/diseases-conditions/vitamin-defic... [1]:https://www.nhlbi.nih.gov/health-topics/pernicious-anemia

> Phytoplankton eat bacteria, correct?

No, phytoplankton are basically microscopic plants, they don't eat anything per se, they are autotrophs which use inorganic substances in the environment and get their energy from sunlight.

> Key here is beneficial bacteria and fungi, which a lot of our foods are increasingly poor in.

Aren't the beneficial bacteria and fungi that are meant to inhabit our own guts supposed to be enough?

Historically, maybe. But they do their work in the colon where it's too late for most nutrients to be absorbed without a "reconsumption" step humans generally no longer practice.

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