On Power Plant Protein

Choosing in this aisle is mostly about which plant it's made from and what you're avoiding. These are the questions our naturopaths ask in store, so you take home the right tub.

A good fit if

• You're vegan or dairy intolerant, or whey just doesn't agree with you, and you still want the protein
• You're training and food alone isn't getting you to your daily protein total
• You want the source with the most evidence behind it, which here is soy
• You need to avoid soy as well as dairy. Pea and rice blends are made for that
• You'd rather eat your protein first and use a powder only on days that fall short

Check with us first if

• You take thyroid medicine. Soy and levothyroxine have a long-known interaction that affects how the medicine is absorbed, so the usual advice is to take them at different times.
• Your kidneys don't work well. Eating more protein, from any source, is worth raising with your doctor before you start.
• You're pregnant or breastfeeding. Nothing specific to plant protein is known to be a problem, but a concentrated supplement is still worth a chat.
• Your gut is sensitive, or you follow a low FODMAP diet. Less refined concentrates tend to sit heavier than isolates.
• You're allergic to another legume, nut or seed. These powders get reformulated, so what was safe in your last tub may not be in this one.
• You take prescription medicine. Check with your doctor, pharmacist or our naturopaths before you start.

• Pea protein isolate. Best known for: The usual vegan base on Australian shelves, and the one plant source with its own training trial here. Absorption: Not measured in this evidence. We hold no verified absorption comparison against whey or the other plant sources. Typical use: The trial ran for 12 weeks in 161 men at 25 g twice a day. Across the whole group, the difference against whey and placebo was a trend, not a significant result, and the clear advantage over placebo showed only in the men who were weakest at the start. It tested a named commercial pea isolate, so keep in mind the trial had a commercial interest.
• Soy protein isolate. Best known for: The most studied plant protein for training results, and the only one in this family with a meta-analysis behind it. Absorption: We hold no direct absorption figure. What we do have is nine trials showing it matched animal protein for strength and lean muscle. Typical use: The strongest evidence in the family, but also the one source many people can't use, because soy is a declared allergen. None of the soy evidence carries over to pea, rice, hemp or a blend.
• Rice protein isolate. Best known for: Usually the second source in a blend rather than the whole powder, and the common choice for people avoiding soy as well as dairy. Absorption: We hold no verified figure. Typical use: There's no verified training trial behind rice protein here. It's chosen for the formula and for tolerance, not because of evidence.
• Hemp protein. Best known for: Pressed from the whole hemp seed rather than isolated from it, so it's the least refined powder in the group. Absorption: We hold no verified figure. Typical use: There's no training trial behind it here either. Hemp seed protein has no entry at all on the medicines ingredient list, which fits with it being regulated in Australia as a food.
• Pea and rice blend. Best known for: The most common formula on the shelf, and the standard answer if you're avoiding dairy and soy at the same time. Absorption: We hold no verified figure. Typical use: We hold no trial of a blend. Combining two sources is the manufacturer's choice, and any complete-protein wording should be based on an amino acid test of that exact product.

Reference values. There isn't one on a powder label, because protein is a macronutrient (one you need in large amounts) rather than a vitamin or mineral. The Australian reference tables we use cover vitamins and minerals but not protein, so we'd rather leave it out than quote a number we can't source. What you need depends on your weight, your age and how hard you train.

Typical supplemental range. Two confirmed trial doses are worth knowing before you look at a scoop size. The pea trial used 25 g twice a day, 50 g in total, which is more than the single daily serve most labels suggest. The diet study didn't use a scoop at all: it topped total daily protein up to 1.6 g per kilogram of body weight, roughly 115 g a day for a 73 kg person, including food.

Upper level. We don't know of one, and there's no daily limit on pea, soy or rice as permitted ingredients. That doesn't mean you should keep adding scoops. Once you've reached your daily total, extra powder just gives you protein you've already covered.

Worth knowing. A powder tops up your meals rather than replacing them, and it does the most around training, which gives your body a reason to use it. What you need depends on your age, diet and health, so talk to one of our naturopaths.

If any of these sound like you, talk to one of our naturopaths or your doctor before you start.

• Soy allergy. Soy protein is a declared allergen with a risk of anaphylaxis. Don't take any powder containing soy.
• Thyroid medicine. Soy has long been known to affect how levothyroxine is absorbed, so the two are usually taken at different times.
• Kidney problems. A high total protein intake from any source needs medical advice first.
• Pregnancy and breastfeeding. There's no recorded reason to avoid plant protein specifically, but check with a practitioner as you would for any concentrated supplement.
• FODMAP sensitivity and IBS. Less refined protein concentrates can cause bloating and tummy discomfort.
• Other legume, nut or seed allergies. These are blended products, and formulas change between batches and flavours.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before you start.