Turmeric gets metabolized quickly in the liver and intestinal walls. Nano-emulsions get around this because they are 99% absorbed in the esophagus and stomach which don't have the same enzymes. Unfortunately they require special equipment, and have a weirdness factor attached to them. You can find the same technology being applied to Cannabis tinctures.
The other approach everyone knows about is combining it with "black pepper", because piperine, a known inhibitor of hepatic and intestinal glucuronidation, allows for the buildup in the bloodstream of turmeric. Caution is urged—as with grapefruit—because pepper can prevent medicines from breaking down by slowing down the liver.
Despite all the hubbub over garlic and essential oils and citrus fruits, any in vitro "anti-viral" activity likely only occurs far above real-life concentrations. An average 70kg male needs around 100 cloves of garlic per day worth of diallyl disulfide[1] to inhibit the common influenza and herpes virus.
In contrast, the immune-stimulating β glucans in common mushrooms are able to facilitate a whole-of-immune-system boost at a dose of 50-400mg, and the Vitamin D2 you can get by exposing them to sunlight or UV light for 8 hours is active at 1000 times lower concentration.. in the microgram range.
I ultimately found white buttons and shiitakes better for allergies than the quercetin in capers/red onions. The two compliment each other, actually.
Mushrooms contain many bioactive components including polysaccharides, glycoproteins, proteins, lipids, and secondary metabolites [1]. Polysaccharides composed of glucose, mannose, galactose, fucose, arabinose, glucuronic acid, and β-d-glucan are the most potent substances of mushrooms that show demonstrable beneficial properties such as antioxidant [2], immune-stimulatory [3,4] lipid lowering [5,6], and anti-tumor activity [7,8,9].
However, when discussing the biological activities of whole mushroom or its extracts, chemical structure, and extraction protocols need to be considered as water extracts usually activate immune cells whereas ethanol extracts inhibit them [10]. Thus, processing of the mushroom may determine the effect produced on immune cells, possibly due to different solubility and potency of specific compounds [10,11]. Edible mushrooms have been studied extensively for their immune modulating properties in animal models including β-glucan-induced anti-inflammatory effects [3,12], enhanced NK cell activity [11,13], improved dendritic cell (DC) maturation and function [14], increased cytokine production [15], increased protective immunity from Salmonella vaccination [16], and anti-inflammatory effects in patients with ulcerative colitis and Crohn’s disease [17,18,19,20].
Health promoting prebiotic effect has been shown after feeding some medicinal [21,22] and white button (WB)-raw mushrooms [23,24,25] in animal models.
The gastrointestinal (GI) microbiota perform numerous biological activities for the host [26] including facilitating nutrient availability, energy harvest and carbohydrate metabolism, and processing indigestible plant components [27]. Metabolic enzymes encoded in microbial genomes and released in the intestine will degrade dietary polysaccharides into short chain fatty acids (SCFA) that induce systemic anti-inflammatory activities on the host [25,28] and synthesize essential amino acids and vitamins [29].
For a while there was also a lot of talk about Agaricus blazei—God's or the Almond mushroom—but there's not enough evidence to prefer one over the other, there seems to be a lot of overlap.