Whey protein is popular for good reason: it's convenient, it mixes easily and it's one of the most studied proteins around. For most people it isn't "bad." But plenty of people feel better without it, and some of the reasons are real while others don't hold up. Here's an honest look at both, and at what to choose instead if whey isn't for you.
Is whey protein safe for most people?
Whey is one of the two main proteins in milk. Dairy protein is about 80% casein and 20% whey, and whey is the "fast" one, digested and absorbed quickly. A systematic review of whey supplementation found that most reported adverse effects were tied to chronic, excessive use without professional guidance, with the kidneys and liver the organs most often affected, and it called for better long-term studies. In ordinary amounts, as part of a balanced diet, whey is a normal dairy food.
If you have kidney or liver disease, or you're pregnant or taking medication, talk to your doctor before adding any protein supplement.
Why does whey upset some people's stomachs?
Lactose is the usual culprit. Experts estimate that about 68% of the world's population, and about 36% of people in the US, have lactose malabsorption, a reduced ability to digest the sugar in milk. Not everyone with malabsorption gets symptoms, but those who do can have bloating, gas and diarrhea. Whey concentrates keep more lactose than isolates, so they're more likely to cause trouble.
Milk is also one of the nine major food allergens in the US. A milk allergy is an immune reaction to milk proteins, which can include whey, and it's different from lactose intolerance. If you suspect an allergy, see a doctor rather than experimenting on your own.
What about antibiotics and growth hormones in dairy?
This is where older warnings about whey went too far. The FDA approved the dairy hormone bovine somatotropin (rbST) in 1993 and states that milk from treated cows is safe to drink, in part because bST is a protein that is broken down in digestion and has no activity in humans. The European Union does not allow its sale or use in dairy cows, so rules differ by country.
Milk is screened for antibiotic residues, though a 2015 FDA survey reported by NPR found residues in about 0.4% of randomly collected samples, all from drugs that routine tests don't look for. If either issue matters to you, USDA organic standards require organic dairy animals to eat 100% organic feed, and an animal treated with a prohibited substance can't be sold as organic.
Is there a link between whey, IGF-1 and cancer?
Insulin-like growth factor 1 (IGF-1) is a hormone that stimulates cell growth. In a well-known Harvard study, men in the highest quarter of blood IGF-1 levels had 4.3 times the prostate cancer risk of men in the lowest quarter. A later meta-analysis found that milk intake is associated with higher IGF-1 and suggested IGF-1 as a possible link between milk and prostate cancer.
That's a reason for curiosity, not alarm. These studies measured milk and blood IGF-1 levels, not whey supplements, and they show associations rather than cause and effect. If you have a personal or family history of prostate cancer, it's worth discussing your diet with your doctor.
Does whey weaken your bones?
No. Earlier versions of this article said animal protein "leaches" calcium from bones and that whey raises osteoporosis risk. The evidence doesn't support that. A National Osteoporosis Foundation meta-analysis found no adverse effects of higher protein intakes on bone, and moderate evidence that more protein may help lumbar spine bone density.
The 2000 study we used to cite compared soy protein with whey in perimenopausal women. Its conclusion was that soy isoflavones attenuated bone loss; whey was the comparison group, and the researchers did not conclude that whey raises osteoporosis risk. For more on bone health, read what osteoporosis is.
What's a good alternative to whey?
If dairy doesn't agree with you, or you'd simply rather eat plants, a well-made plant protein covers the same needs. So Lean & So Clean provides 23g of complete organic plant protein per serving from organic pea and rice protein, with no added sugar and no artificial sweeteners, fillers or gums. For what to look for on any label, see how to choose a clean plant-based protein powder, and for more on whey itself, what whey protein is.
