Clean Sourcing by Food Category

Meat

Grass-fed/finished vs conventional: the difference is real but nuanced. Grass-fed beef has 2-5x more omega-3 fatty acids, higher CLA (conjugated linoleic acid), more vitamin E and beta-carotene. The omega-6:3 ratio shifts from ~20:1 (conventional) to ~3:1 (grass-finished). Absolute amounts are still small compared to fish.

Antibiotics: 80% of antibiotics sold in the US go to livestock. Conventional poultry and pork are the highest-use categories. "No antibiotics ever" labeling is USDA-verified. "Raised without antibiotics" is less regulated.

Priority order: (1) avoid processed meats entirely (WHO Group 1 carcinogen), (2) choose "no antibiotics ever" poultry and pork, (3) grass-finished beef if budget allows, (4) pasture-raised eggs over cage-free over conventional.

Produce

EWG's Dirty Dozen (highest pesticide residue, prioritize organic): strawberries, spinach, kale/collard greens, peaches, pears, nectarines, apples, grapes, bell peppers, cherries, blueberries, green beans.

Clean Fifteen (lowest residue, conventional is fine): avocados, sweet corn, pineapple, onions, papaya, frozen peas, asparagus, honeydew, kiwi, cabbage, mushrooms, mangoes, sweet potatoes, watermelon, carrots.

The pattern: thick-skinned produce you peel has less residue. Thin-skinned berries and leafy greens that are eaten whole have the most. Washing removes some surface residue but not systemic pesticides absorbed into the plant tissue.

Dairy

A1 vs A2 beta-casein: most commercial dairy (Holstein cows) produces A1 beta-casein, which releases BCM-7 (beta-casomorphin-7) during digestion. Some studies link BCM-7 to digestive discomfort and inflammation. A2 dairy (from Jersey, Guernsey, Brahman cows, or goats/sheep) does not produce BCM-7. Many people who think they're lactose intolerant actually tolerate A2 dairy fine.

Raw vs pasteurized: raw dairy retains enzymes (lipase, lactase, phosphatase) and beneficial bacteria destroyed by pasteurization. Risk: unpasteurized milk can carry Listeria, Salmonella, and E. coli. Legal status varies by state. The evidence for health benefits of raw dairy is largely observational (farm children studies).

Priority: organic dairy avoids rBGH/rBST growth hormones and reduces antibiotic residue. A2 dairy if you experience digestive issues with conventional. Grass-fed butter has more K2 and omega-3s (visible in its deeper yellow color).

Grains

Glyphosate in wheat and oats: glyphosate (Roundup) is sprayed on conventional wheat and oats as a pre-harvest desiccant -- the crop is killed to dry it for easier harvest. This means residue is directly on the grain at its highest concentration at the moment of harvest. EWG testing found glyphosate in 95% of oat-based foods tested.

Arsenic in rice: rice absorbs arsenic from soil and water at 10x the rate of other grains. Brown rice has more arsenic than white (concentrated in the bran). Basmati rice from California, India, or Pakistan tends to have lower arsenic than rice from the southern US (former cotton fields treated with arsenical pesticides).

Mitigation: buy organic oats and wheat products. Rinse rice thoroughly and cook in excess water (6:1 water to rice, drain), which reduces arsenic by 40-60%. Rotate grains rather than eating rice daily.

Seafood

Mercury by species (FDA/EPA data):

Wild vs farmed: wild salmon has fewer contaminants (PCBs, dioxins) and better omega-3:6 ratio. Farmed salmon is fed grain-based feed which shifts fatty acid profile. Farmed salmon is still nutritious but higher in total fat, PCBs, and sometimes antibiotics. Wild Alaskan salmon (sockeye, coho) is the cleanest option.