Whey protein linked to cancer promotion:
The hormone IGF-1 only occurs in animal protein, one of the best sources being protein from cow’s milk. IGF-1 has been shown to promote cancer cell growth in humans. Studies show that increased levels of IGF-1 lead to increased growth of existing cancer cells. Dietary interventions and modifications such as vegan diets have been shown to down regulate (make less of) IGF-1 and have been associated with lower risk of cancer. It has been proven that people with exceptionally low levels of IGF-1 (Laron syndrome) are resistant to cancer. IGF-1 does not occur in plant protein and plant protein has not been shown to promote cancer growth.
Whey protein linked to aggravation of acne:
According to studies, healthy male adults may develop acne after the consumption of whey protein. The studies indicate that dairy protein enhances IGF-1 and acne aggravation. Plant protein has not been linked to acne.
Whey protein linked to flatulence, bloating, cramps, diarrhea, nausea and rumbling stomach:
Seventy-five percent of all African American, Jewish, Mexican American, and Native American adults are lactose intolerant. Both whey concentrate and whey isolate contain lactose. However, whey concentrates contain higher amounts of lactose. Lactose intolerant people will suffer a variety of digestive issues which may include abdominal bloating, cramps, flatulence, diarrhea, nausea, vomiting and a rumbling stomach. Lactose only occurs in dairy protein and does not occur in plant protein.
Whey protein may cause constipation:
Numerous studies concluded that constipation in children can have an allergic pathogenesis to whey and other dairy proteins. Plant protein has not been linked to constipation.
Whey protein can dangerously lower blood sugar:
Whey protein has been shown to lower blood sugar. Caution is advised for people with diabetes or low blood sugar and in those taking drugs that affect blood sugar. According to Mayo Clinic, blood sugar levels may need to be monitored by a qualified healthcare professional and medication adjustments may be necessary for those consuming whey protein. Plant protein has not been shown to have effects on blood sugar.
Whey protein may cause abnormal heart rhythms:
According to Mayo Clinic, whey protein may cause abnormal heart rhythms. Plant protein has not been shown to effect heart rhythms.
Whey protein may cause headaches:
According to Mayo Clinic, whey protein may cause headaches.  Plant protein has not been linked to headaches.
Whey protein may increase the risk of diabetes:
According to Mayo Clinic, whey protein may increase the risk of diabetes.  Plant protein has not been linked to increased risk of diabetes.
Whey protein may increase the risk of bleeding:
According to Mayo Clinic, whey protein may increase the risk of bleeding. Caution is advised in people with bleeding disorders or in those taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary. Plant protein has not been shown to increase the risk of bleeding.
Whey protein may cause drowsiness:
According to Mayo Clinic, drowsiness or sedation may occur when consuming whey protein. They advise using caution if driving or operating heavy machinery. Plant protein has not been linked to drowsiness or sedation.
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