Supplements and type 2 diabetes: what lowers blood sugar, what doesn't, and where collagen fits

If you have type 2 diabetes, or your doctor has said "prediabetes", you have probably been offered a supplement that "controls blood sugar". Most don't. This guide covers the 2 things that do move blood sugar in trials, which supplements have weak or no evidence, and how to use Health Nut's products safely alongside a diabetic diet, which is as a source of carb-free protein and nothing more.

The 2 things that actually work

1. Fewer carbohydrates. A 2021 BMJ review pooled 23 trials (1,357 people with type 2 diabetes). At 6 months, 57% of those on a low-carb diet (under 130g of carbs a day) had an HbA1c below 6.5%, the remission threshold, against 31% on control diets. Weight, triglycerides and insulin sensitivity all improved. The honest caveats: the effect faded by 12 months as people drifted back to old habits, it was much smaller in people on insulin, and "very low carb" (keto) was no better than moderate low carb unless people stuck to it rigidly. The lesson is that carbs drive blood sugar, and cutting them works for as long as you keep doing it.

2. Weight loss, if you carry extra. The DiRECT trial in UK GP practices put 149 people with recent type 2 diabetes on a structured weight-loss programme. At 1 year, 46% were in remission, off all diabetes medicine, against 4% of controls. Remission tracked weight loss almost exactly: 7% of those who lost under 5kg, 34% at 5 to 10kg, 57% at 10 to 15kg, 86% at 15kg or more. It was done with a formula diet and medical supervision, which you should not copy at home, but the message is clear: in early type 2 diabetes, losing weight can reverse it.

Both of these are things you eat less of, not things you buy. Any supplement has to be judged against that.

Supplements: what the evidence says

• Cinnamon. The best-known one. A meta-analysis of 10 trials (543 people) found it lowered fasting glucose by about 1.4 mmol/L and improved cholesterol, but had no significant effect on HbA1c, the 3-month average that actually matters. Results varied widely between trials and the right dose is unknown. Harmless in food amounts; not a treatment.
• Chromium, magnesium, alpha-lipoic acid, berberine. Small, mixed trials. Berberine has the most promising data but interacts with several medicines. None replaces metformin, and none should be started without telling your doctor.
• Bicarbonate of soda. It does not lower blood sugar. An earlier version of this article said bicarb helps with diabetic ketoacidosis; that is hospital intravenous treatment for a medical emergency, and has nothing to do with baking soda at home. Bicarb is also sodium, which matters because most people with type 2 diabetes also have high blood pressure. If you use it for indigestion, keep it to the occasional ¼ teaspoon.
• Silica. No human trials in diabetes. An earlier version of this article claimed silica "helps treat diabetes"; it does not, and we have removed the claim. Alexia-Rich silica is a hair, skin and nail supplement.
• Collagen. Does not lower blood sugar either. What it does do is add protein without carbohydrate, which is where it earns a place on a diabetic shelf.

Where Health Nut products fit

Our collagen powders (Restore, Vibrance, Active) are 0g carbohydrate and 0g sugar per serving, so they do not count towards your carb allowance and do not raise blood glucose. Protein with a meal slows the rise in blood sugar from the carbs you do eat, and it keeps you full, which makes a lower-carb diet easier to hold. A scoop in morning coffee or a smoothie is a simple way to add about 10g of protein to a breakfast that would otherwise be mostly carbohydrate.

That is the whole claim. They support a low-carb way of eating; they are not a diabetes treatment and should never replace one.

Alexia-Rich silica (liquid, capsules and the smoothie powder) is also carb-free, so it fits the diet, but take it for hair, skin and nails, not for blood sugar.

The practical version

1. Cut sugary drinks, fruit juice and refined starch (white bread, pap, rice, pasta) first. These are the carbs that spike glucose fastest.
2. Build meals around protein and vegetables; add moderate whole-food carbs (beans, oats, sweet potato) to taste and to your meter.
3. If you're overweight, aim to lose it slowly and steadily with your doctor's knowledge. Every 5kg matters.
4. Walk after meals. 10 to 15 minutes lowers the post-meal glucose rise.
5. Use a collagen scoop where you need carb-free protein: coffee, smoothies, soups.
6. Keep taking your medicine. Let your HbA1c, not a supplement label, tell you when it can change.

Frequently asked questions

Does collagen raise blood sugar?
No. It is protein with no carbohydrate or sugar. Protein can prompt a small insulin release, which is normal and helps clear glucose.

Is keto better than ordinary low-carb for diabetes?
In the trials, not unless people followed it very strictly. Moderate low-carb (under 130g a day) is easier to keep up and gave similar results. Talk to your doctor before trying keto if you're on medication.

Can type 2 diabetes really go into remission?
In early diabetes with meaningful weight loss, yes: 46% in the DiRECT trial at 1 year. It needs to be done with medical support, and it needs to be maintained.

Should I take cinnamon?
If you like it, use it in food. Don't rely on it; it hasn't been shown to change HbA1c.

What about type 1 diabetes?
Nothing here replaces insulin. Carb-free protein still fits a type 1 diet, but any change to eating pattern needs your diabetes team's input on insulin dosing.

The sources

• Goldenberg JZ et al. (2021). Efficacy and safety of low and very low carbohydrate diets for type 2 diabetes remission: systematic review and meta-analysis. BMJ 372:m4743. View →
• Lean MEJ et al. (2018). Primary care-led weight management for remission of type 2 diabetes (DiRECT): an open-label, cluster-randomised trial. Lancet 391:541–551. View →
• Allen RW et al. (2013). Cinnamon use in type 2 diabetes: an updated systematic review and meta-analysis. Annals of Family Medicine 11:452–459. View →

Find out more

• How much sugar is too much? Hidden sugars on South African labels
• Collagen on a keto diet: what it adds, and what it doesn't
• Fasting: what intermittent fasting can and can't do
• High blood pressure: 7 lifestyle changes with the numbers to back them
• Which collagen should I use? Vibrance, Restore and Active compared
• Health and ingredient guides

This article is general information, not medical advice. Diabetes is managed with your doctor or diabetes nurse. Do not change your diet, medicine or supplements without telling them, especially if you use insulin or are at risk of low blood sugar.

Also in Health