Don't. You don't want to raise DHT.
DHT, (Di-HydroTestosterone), is a by product of too much Testosterone and can cause baldness.
You could elevate Test levels themselves I believe, by increasing Zinc and Vitamin E levels and slightly reducing Fibre if you have a bit too much, as Fibre is supposed to have some kind of blunting effect on Test.
However Fibre should be consumed at around 35-50g per day, to maintain good stool condition, so you don't increase the risk of constipation from too little, or potentially Diarrhoea if you consumed way too much.
Trust me though, raising DHT is not in your best interests.