Protein supplements have been used for many years in the fitness industry to provide protein needed for muscle growth and endurance.  Most people who work out routinely, particularly those who are interested in bodybuilding or other weight training and strength activities find that a “regular” diet does not provide enough protein to accomplish their goals.  Attempting to increase your protein intake with food can cause you to consume too many calories – which means that you will need a protein supplement.
For many years, “milk” protein containing a combination of casein and whey was the only choice for protein supplements.  Soy protein was introduced when some became interested in avoiding animal products; however soy has issues as it may not be a complete protein and it may cause “estrogenization” as it contains estrogen-like phytochemicals which may encourage feminization and actually prevent muscle growth.  In addition, excessive consumption may increase the risk of feminization which can theoretically lead to similar problems to those caused by hormone supplementation.

Technology has now allowed us to separate casein and whey into their unique parts. Casein is used in some protein supplements and is part of the protein that is claimed as “milk proteins”.  Casein is a high quality protein but is more difficult to digest – it is used in fitness supplements and protein shakes for its “staying power” as it takes longer to absorb. Whey, on the other hand, is easier to digest and contains many essential amino acids.
Whey is also considered the “best” in protein supplements by a lot of fitness experts because of its “completeness” in terms of amino acid content and its ability to be digested easily.  Though most people can tolerate and easily digest whey protein isolate, it may have a number of side effects for some people, and should be completely avoided by others who take certain medications.

Side Effects:
Increased bowel movements due to extra protein load
Bloating in the digestive system due to protein digestion
Cramps in the digestive system for the same reason
Thirst
Nausea
Reduced appetite
Some people also experience side effects that may or may not be related such as
Nausea
Headaches
Fatigue

Drug Interactions: Whey can interact with numerous medications due to its effects on blood glucose, blood pressure, and its interference with the liver’s cytochrome P450 system in processing drugs.

Levodopa – most commonly used for movement disorders such as Parkinson’s disease or due to side effects from some psychiatric medications.  Whey protein may decrease the amount of levodopa which is absorbed by the body.  This will decrease the effectiveness of the medication and may lead to a return of disease state symptoms.  People who are taking levodopa SHOULD NOT take whey protein supplements and should not consume dairy products at the same time that the medication is taken.
Alendronate – also known by the brand name Fosamax, is used to decrease bone loss in osteoporosis.  Whey protein has been shown to decrease bone loss overall as it increases muscle strength which maintains bone but people who have osteoporosis and are taking alendronate may experience decreased effectiveness of the medication.  People who are taking alendronate are cautioned against using Whey.
Quinolone type antibiotics such as levofloxacin, ciprofloxacin and others – may also decrease the amount of medication that is absorbed when taken at the same time.  This will make the medication less effective in treating the infection it was prescribed for.  Whey protein should not be consumed at the same time or within an hour of taking a quinolone antibiotic.  Any antibiotic with the warning “Do not take with dairy” should not be taken at the same time as whey protein.
Tetracycline type antibiotics – similar to quinolone antibiotics, should not be taken at the same time as whey protein.  The protein may bind to the antibiotic and make it ineffective to lack of absorption.  Common tetracycline antibiotics include tetracycline, minocycline and doxycycline. You should take your Whey 2 hours before or 4 hours after taking this type of antibiotic.
Anti-diabetic medication – may be increased in effectiveness by whey protein.  As whey protein may lower blood sugar levels, those taking medication for diabetes may find that their blood sugar is too low.  People with diabetes should closely monitor blood sugar levels and consult a physician who may recommend medication adjustments.
Anti-hypertensive medication – may be increased in effectiveness by whey protein as it may lower blood pressure levels.  Caution is advised in those taking medications that lower blood pressure.
Blood thinners – whey protein may increase the risk of bleeding in those who take blood thinners such as aspirin, warfarin, heparin, clopidogrel and even some non-steroidal anti-inflammatory agents such as ibuprofen or naproxen.
Medications metabolized by the liver – may show altered medication levels which could result in changes in how well the medications work.  People who take any medications should check with a pharmacist or physician before using whey protein supplements.

While whey is truly one of the best protein supplements you can find, this article should show you that it is most definitely not for everyone. Consider everything from lactose intolerance to the over the counter medications you may be taking daily before choosing your protein supplement. And always tell your Provider that you are using whey when they prescribe you a new medication.