Functional Foods by Wellness Goal
A guide to functional foods by wellness goal: cholesterol, blood sugar, blood pressure, gut, brain, inflammation and pregnancy, with where trial evidence is strong, limited or missing.
Content last updated . This page has not been medically reviewed.
Safety first. Natural products can cause side effects and interact with medicines. Read functional food safety before you use anything on this page.
This page is an index. Each goal below links to a page that says which foods were studied, what was measured and how strong the evidence is. It is information only: it is not advice to treat a condition, it gives no diet or meal plan, and foods do not replace medicines. If you take prescribed medicines, ask the prescriber or pharmacist before changing your diet, and read Functional Food Safety first.
How to read the labels on these pages
Established means pooled randomized trials or an official body support a modest effect on a measured marker. Promising but limited means small or short trials, or high variation. Mixed means results differ. Insufficient evidence and Proper evidence not found mean we looked in the sources named and did not find usable studies. A change in a blood marker (such as LDL cholesterol) is not the same as fewer heart attacks, and food studies are often observational. See how to read nutrition research headlines and Functional Food Research and Evidence.
Goal by goal
| Goal | What the evidence looks like | Read |
|---|---|---|
| Cholesterol and heart health | Pooled trials found small LDL drops with oat beta-glucan (0.25 mmol/L) [1], soy protein (4.76 mg/dL) [2] and walnuts (5.51 mg/dL). [3] A Mediterranean-style diet beat a low-fat diet for major cardiovascular events in 1,002 people with coronary heart disease, with no difference in the women in that trial. [4] | More about Cholesterol and heart health → |
| Blood sugar | Low glycemic index or load eating patterns lowered HbA1c by 0.31% in people with diabetes, with high certainty. [5] Other foods have limited or mixed evidence. | More about Blood sugar → |
| Blood pressure | The DASH pattern and lower sodium have trial support; beet juice lowered systolic pressure 5.31 mmHg with low certainty. [6] Potassium needs kidney and medicine care. | More about Blood pressure → |
| Gut health and bloating | A review of kefir trials called the evidence limited, with 12 of the studies at high risk of bias. [7] In a crossover trial of 87 healthy people, sauerkraut changed some single bacterial species, yet the gut microbiome was rather resilient to a short-term change. [8] | More about Gut health and bloating → |
| Brain health and memory | One 12-week trial in 61 healthy older adults found better immediate recall and task switching with wild blueberry powder than placebo. [9] That is one small trial, not a firm result. | More about Brain health and memory → |
| Inflammation | Claims are often broader than the studies. This page set checks them one by one. | More about Inflammation → |
| Pregnancy | Official bodies, not individual foods, are the right starting point. Ask your clinician before diet changes in pregnancy. | More about Pregnancy → |
Goals without a page here
This library has no goal page for weight loss, menopause, bone health, eye health, exercise performance, children or older adults, and it gives no weight-loss or calorie advice. For soy foods and isoflavones, see soy foods. For goal-level advice beyond food, see Wellness Goals.
Single-food guides
The goal pages draw on the food guides, for example oats, legumes, walnuts, beets and blueberries. The full list is in the A to Z directory.
Frequently asked questions
Which foods lower cholesterol?
In pooled trials, oat beta-glucan, soy protein and walnuts each lowered LDL cholesterol a little compared with control diets. No review we read ranks them. [1][2][3]
Is there one best food for a health goal?
We did not find trials that compare foods head to head, and these pages do not rank foods. Evidence is strongest for eating patterns, such as low glycemic index diets for HbA1c. [5]
Are the effects of foods large?
Mostly small. For example, oat beta-glucan lowered LDL by 0.25 mmol/L in a meta-analysis of 28 trials. [1]
Do fermented foods fix gut problems?
A review of kefir trials said evidence was limited and many studies had high risk of bias. [7]
Can food replace my medicine?
No. Ask the prescriber or pharmacist before changing how you take any medicine. See medication interactions.
References
- Whitehead A et al. Cholesterol-lowering effects of oat β-glucan: a meta-analysis of randomized controlled trials. Am J Clin Nutr 2014. Read 2026-10-22.
- Blanco Mejia S et al. A Meta-Analysis of 46 Studies Identified by the FDA Demonstrates that Soy Protein Decreases Circulating LDL and Total Cholesterol Concentrations in Adults. J Nutr 2019. Read 2026-10-22.
- Guasch-Ferré M et al. Effects of walnut consumption on blood lipids and other cardiovascular risk factors: an updated meta-analysis and systematic review of controlled trials. Am J Clin Nutr 2018. Read 2026-10-22.
- Delgado-Lista J et al. Long-term secondary prevention of cardiovascular disease with a Mediterranean diet and a low-fat diet (CORDIOPREV): a randomised controlled trial. Lancet 2022. Read 2026-10-22.
- Chiavaroli L et al. Effect of low glycaemic index or load dietary patterns on glycaemic control and cardiometabolic risk factors in diabetes: systematic review and meta-analysis of randomised controlled trials. BMJ 2021. Read 2026-10-22.
- Grönroos R et al. Effects of beetroot juice on blood pressure in hypertension according to European Society of Hypertension Guidelines: A systematic review and meta-analysis. Nutr Metab Cardiovasc Dis 2024. Read 2026-10-22.
- Kairey L et al. The effects of kefir consumption on human health: a systematic review of randomized controlled trials. Nutr Rev 2023. Read 2026-10-22.
- Schropp N et al. The impact of regular sauerkraut consumption on the human gut microbiota: a crossover intervention trial. Microbiome 2025. Read 2026-10-22.
- Wood E et al. Wild blueberry (poly)phenols can improve vascular function and cognitive performance in healthy older individuals: a double-blind randomized controlled trial. Am J Clin Nutr 2023. Read 2026-10-22.