Review: Nature's Best Zero Carb Isopure® Protein Powder

Review: Nature’s Best Zero Carb Isopure® Protein Powder

Nature’s Best Zero Carb Isopure contains 50 grams of protein from 100% Whey Protein Isolate. Any and all impurities typically found in most whey proteins have been removed to provide you with a great tasting, lactose-free, aspartame-free, fat-free, gluten-free, glutamine-enriched, state of the art carbohydrate-free protein powder.”

Nature’s Best calls their Zero Carb Isopure “The Elite Protein Elixir.” Isopure lives up to its name: in addition to being carb-free, it contains barely a gram of fat. This is in contrast to most other commercial whey protein powders, which typically contain 2–5 g carbs (from lactose) and 1–3 g of fat.

How can Isopure be so low in carbs? The answer lies in the purification process. The dominant protein source used in Isopure is an ion-exchange whey isolate.

Each amino acid has a side chain, that contributes to the shape and function of the protein its a part of. Some of these ionize quite easily, and give the protein a net charge that’s dependent on pH (a measure of acidity/alkalinity).

This is a property that can be used to separate and purify proteins, via a technique known as “ion-exchange chromatography.” In essence, the pH of a liquid containing a mixture of proteins can be adjusted so that the proteins of interest in a mixture have a net positive or negative charge. When the solution is passed over an oppositely charged matrix, these proteins “stick,” while the other components pass through. The “stuck” proteins can then be removed simply by changing the conditions and washing them out.

Needless to state, not all whey protein supplements are produced this way. Many other commercial whey protein isolates and concentrates are now purified using ultrafiltration or microfiltration techniques. These processes separate proteins by their size, rather than charge.


At this point, I’ll bet you’re wondering why I’m even discussing this. Does anyone really care about the manufacturing method when they choose a whey protein supplement?

Believe it or not, quite a few people do. Welcome to the great “ultra/microfiltration vs. ion-exchange debate.” Allow me to explain…

Ion-Exchange vs. Micro/Ultrafiltration

To begin, “whey protein” isn’t a single protein. It’s a complex mixture of proteins, each with different properties.

The major/minor whey proteins that have been identified in cow’s milk are:

  • Beta-lactoglobulin (approx. 50%)
  • Alpha-lactalbumin (approx. 25%)
  • Bovine Serum Albumin
  • Immunoglobulins (antibodies): IgG1, IgG2, IgA, IgM
  • Glycomacropeptide
  • Lactoferrin
  • Lactoperoxidase
  • Lysozyme
  • Beta2-microglobulin

As it turns out, some of these proteins are biologically active and have health-promoting effects. Lactoferrin, lactoperoxidase, lysozyme, glycomacropeptide and the immunoglobulins, for example, have anti-microbial and immune-enhancing activities. Whey protein-derived peptides can reduce high blood pressure and other risk factors for cardiovascular disease. Whey peptides even have anti-tumor effects.

This is where the manufacturing method comes into the picture.

One charge that has been leveled at the ion-exchange process is that it selects for the major—and less interesting—proteins like beta-lactoglobulin, and depletes the smaller, more bioactive fractions.

This is not a problem with filtration purified products, as these minor proteins are retained. Some experts advise people to purchase ultra/microfiltered whey protein for this reason, as they feel the “nutraceutical” effects are important.

Personally, I’m somewhat skeptical. It’s true that lactoferrin, etc. are useful and valuable proteins, but each represents no more than < 1% – 2% of the total whey protein prior to purification. Thus, whether they’re present in amounts capable of exerting significant biological effects is questionable—especially when the protein is consumed in supplemental (vs. therapeutic) amounts.

It’s also unclear which whey peptides have anti-hypertensive and anti-cancer activities; to my knowledge, no comparisons have been made between ion-exchange and ultra/microfiltered sources. Thus, it may be unfair to condemn ion-exchange products, particularly if all you want is a fast digesting protein for pre-/post-workout.

The Bottom Line

Frankly, life is too short to get tied up in your underwear about issues like this. In the end, we’re talking about the differences between an effective, good quality protein supplement…and a possibly value-added, effective, good quality protein supplement.

If you’re intrigued by the potential benefits of a full spectrum whey protein, then you should look for an ultra/microfiltered product. If all you’re looking for is a good, clean protein supplement, however, then there’s no need to get sidetracked by this debate at all. Either one will do.

And Zero Carb Isopure is certainly a good, clean protein supplement. I recently took the “Mango-Peach” flavor for a test drive, and thought it was pretty tasty. It was very light and appropriately fruity when mixed in water. It was even better blended with plain, nonfat yogurt.

Isopure comes in a variety of other flavors and provides a solid 50 g of protein per serving. It also provides ~50% of the RDA for most of the major vitamins and minerals—which is unusual for a protein supplement.

Overall, I’d say Zero Carb Isopure is worth a look, especially for people who are lactose-intolerant, or are on carbohydrate-restricted diets.

Summary of Zero Carb Isopure
  • Good for low-carb diets.
  • Good option for those w/lactose-intolerance.
  • Tastes good.
  • Likely to be lower in biologically-interesting fractions.

Author: elissa

Elissa is a former research associate with the University of California at Davis, and the author/co-author of over a dozen articles published in scientific journals. Currently a freelance writer and researcher, Elissa brings her multidisciplinary education and training to her writing on nutrition and supplements.

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