schultz
Member
- Joined
- Jul 29, 2014
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- 2,653
Peat has specifically mentioned coffee as a source, but I have not seen any compelling evidence that coffee has significant amounts of Mg.
This study: http://www.sciencedirect.com/science/article/pii/S0308814611010880 shows the magnesium content of instant coffee to be quite high, not to mention other minerals.
The pic below was taken from that study...
100g of instant is quite a bit of coffee though. Ray has mentioned he tries to drink 5 strong cups of coffee a day. Based on how much niacin he says this 5 cups has (near 40mg), it seems each one of his strong coffees is equivalent to about 3 cups of regular coffee. I think it would be about 60g of instant coffee.
This study: http://www.ncbi.nlm.nih.gov/pubmed/6650450 has a table showing the mineral content of coffee taken from other studies.
Looking at the data from the 2 Finland studies, you can see that 60g of beans made into a litre of coffee contains 73-80mg of magnesium in the first analysis and 110-120mg in the second analysis.
I personally use 30g of beans to make 1 cup of concentrated coffee (I use it for latte's) and I drink about 5-7 of these a day. Assuming 40mg of magnesium for 30g of beans (which is actually on the lower side according to the table above) I would be getting 200-280mg of magnesium from coffee a day. That's at least half of the RDA for magnesium from a food that has almost zero calories.
Look at the other minerals as well!
From 5 cups of strong coffee (150g of beans) you can get approximately...
1800mg Potassium
220mg Magnesium
1mg of Manganese
36mg of Niacin (depending on roast)
9mg B5
3mg B2
0.5mg B1
1,500mg of Caffeine
So I guess the amount of magnesium may not be significant if you don't drink much coffee, but for people who drink quite a bit, getting 50% of the RDA for magnesium from coffee is quite easy. That seems significant to me.