Small Foods with Powerful Protection

Hi I’m Sammy,

Your Good Farm in-house nutritionist. Here to bring you essential information on nutrition, diet and permaculture gardening - in a bite size, easy to understand, science-backed way.

Small Foods with Powerful Protection

Last week, a friend asked me what I considered to be some of the most protective foods we can include in our diet. More specifically, which foods have the strongest evidence behind them for supporting long-term health and helping to reduce cancer risk.

The conversation was well timed, as I had recently started drinking matcha green tea again and revisiting some of the research on food compounds linked to cellular protection and healthy ageing.

Cancer is a complex disease influenced by genetics, lifestyle, environmental exposures and chance, with many of these factors interacting over decades. While some risk factors are beyond our control, others are not.

Rather than focusing on what we should avoid, reduce or eliminate, this article explores what we can actively include.

Matcha Green Tea

Star Compound: EGCG (Epigallocatechin Gallate)

Matcha originates from Japan, where green tea plants are shade-grown before harvest. Unlike regular green tea, where the leaves are steeped and discarded, matcha involves consuming the entire leaf in powdered form. This results in a much higher concentration of catechins, particularly EGCG, one of the most studied plant compounds in cancer and longevity research. EGCG has been investigated for its antioxidant activity and its ability to support cellular defence, repair and healthy inflammation regulation.

A typical serving of matcha contains around 40–70 mg of caffeine. For comparison, black tea generally contains 40–60 mg per cup, while coffee may contain 80–150 mg or more.

Despite containing caffeine, many people find matcha produces a calmer, more sustained energy than coffee. This is thought to be due in part to its naturally occurring L-theanine content, an amino acid associated with focus and alertness.

Traditionally, matcha is whisked into hot, but not boiling, water. It can also be enjoyed as a latte or added to smoothies. While consuming matcha with water is likely to provide the greatest exposure to its beneficial compounds, enjoying it with milk is still a practical and enjoyable option.

While there is no established optimal dose, 1–2 servings daily (around ½–1 teaspoon per serving) is likely sufficient to provide meaningful amounts of beneficial catechins.

Dark Berries and Purple Foods

Star Compounds: Anthocyanins

When people think of purple foods, they often think of berries first; Blueberries, blackberries and other dark-coloured berries are rich in compounds called anthocyanins. These pigments give plants their deep purple, blue and red colours and have been studied for their antioxidant activity, cellular protection, vascular health and healthy ageing.

One consideration with berries is that conventionally grown varieties can carry relatively high pesticide residues. While organic berries may be the preferred choice, they are not always practical or affordable for regular consumption. Fortunately, berries are not the only source of anthocyanins. Purple sweet potato, purple cabbage, purple cauliflower, purple carrots, purple asparagus, eggplant, purple grapes, plums and black rice all contribute varying amounts of these protective plant compounds and can often be more affordable additions to the diet.

Purple sweet potato has traditionally been consumed in Okinawa, Japan, a region known for its remarkable number of long-lived individuals. Its vibrant colour comes from an exceptionally high concentration of anthocyanins, often rivalling or exceeding that found in many berries.

Interestingly, many vegetables that we now associate with orange, white or green varieties originally existed in purple forms before centuries of cultivation and selective breeding produced the colours most familiar to us today. Purple carrots are perhaps the best-known example, while purple varieties of cauliflower, asparagus and cabbage remain available today.

Anthocyanins are concentrated within the coloured pigments of plants, so retaining skins where appropriate and consuming a variety of deeply coloured fruits and vegetables can help maximise intake. Both raw and cooked forms can contribute valuable phytonutrients, with gentle cooking sometimes improving access to certain compounds by breaking down plant cell walls.

Extra Virgin Olive Oil

Star Compounds: Oleuropein and Hydroxytyrosol

Extra virgin olive oil is a cornerstone of the traditional Mediterranean diet, one of the most studied dietary patterns in the world. Regions associated with exceptional longevity and lower rates of chronic disease often share a common feature: regular consumption of high-quality olive oil as a daily food.

Unlike refined vegetable oils, extra virgin olive oil retains naturally occurring polyphenols, including oleuropein and hydroxytyrosol. These compounds have been studied for their antioxidant activity, support of healthy inflammation regulation and protection against oxidative stress.

When shopping for olive oil, many people automatically gravitate towards European varieties from Spain, Italy or Greece. While these regions produce excellent olive oils, freshness is one of the most important factors influencing quality and polyphenol content.

For Australians, locally produced olive oil is often among the freshest available. Rather than focusing solely on the country of origin, look for a harvest date or production date, which should be displayed on the back on the bottle. The closer the oil is to harvest, the higher its polyphenol content is likely to be. While expiry dates are useful, harvest dates provide a much better indication of freshness. Prioritising smaller glass bottles 1-2 litres over larger 3-5 litre drums also help to maintain freshness.

To further preserve quality, store olive oil in a cool, dark place away from heat and direct sunlight. Light, oxygen and heat gradually degrade both flavour and beneficial compounds over time.

Extra virgin olive oil is ideal for salad dressings, drizzling over vegetables and everyday cooking. Despite common myths, high-quality extra virgin olive oil is relatively stable due to its antioxidant content and can generally be used for most home cooking applications. For very high-heat cooking, other stable fats such as ghee, tallow or avocado oil may also be appropriate options.

Fun fact: A peppery sensation at the back of the throat is often a sign of higher polyphenol content. That slight "bite" comes from the same compounds that contribute to many of olive oil's health benefits.

Garlic and Onions

Star Compounds: Allicin and Organosulfur Compounds

Garlic, onions, leeks, shallots and spring onions belong to the allium family, a group of vegetables associated with numerous health benefits.

As discussed in a previous article, allicin, a compound studied for its antimicrobial, antioxidant and protective properties, is only formed when garlic is chopped, crushed or minced. Allowing it to sit for at least 10 minutes before cooking helps maximise its formation. The broader family of sulphur-containing compounds found within alliums may also support detoxification pathways and cellular defence mechanisms.

One of the simplest ways to increase intake is to use garlic, onions and leeks generously in everyday cooking. When a recipe calls for one clove of garlic, I often use four.

Leeks can also be prepared in advance by gently sautéing a batch, including the green tops, and storing them in the fridge, ready to add to scrambled eggs, omelettes and meals throughout the week.

Fun fact: The compounds that make you cry when chopping onions are the same sulphur-containing compounds that contribute to their unique flavour and many of their nutritional benefits. If you're reaching for the goggles, that's often a good sign.

Broccoli and Cruciferous Vegetables

Star Compound: Sulforaphane

If there were an award for the most researched anti-cancer vegetable family, cruciferous vegetables would be strong contenders.

This group includes broccoli, cauliflower, cabbage, kale, Brussels sprouts, rocket and bok choy. They contain compounds called glucosinolates which, when chopped, chewed or digested, can be converted into biologically active compounds such as sulforaphane. Sulforaphane has been extensively studied for its role in supporting detoxification pathways, cellular defence systems and the body's handling of environmental toxins.

To maximise sulforaphane formation, chop cruciferous vegetables before cooking and allow them to sit for around 30 minutes before heating.

Freshness also matters. Broccoli has one of the highest respiration rates of commonly consumed vegetables, meaning nutrient levels begin declining soon after harvest. When possible, buy it fresh and eat it within a day or two. Farmers' markets and locally grown produce offer many advantages, as less time has passed between harvest and your plate. Hardier vegetables such as cabbage retain their nutritional value for much longer, making them a great option later in the week.

For maximum benefit, chop broccoli into florets and add them to a steamer of rapidly boiling water. Smaller pieces cook more quickly, helping to preserve nutrients and phytonutrients.

Like many plant compounds, absorption may be enhanced when consumed alongside healthy fats. A drizzle of extra virgin olive oil, a knob of butter or a handful of nuts aids bioavailability.

Health Insight: Frost exposure may increase both the sweetness and phytonutrient content of broccoli and kale, making winter one of the best times to enjoy these vegetables.

Mushrooms

Star Compounds: Beta-Glucans and Ergothioneine

Mushrooms contain a unique collection of compounds rarely found elsewhere in the food supply.

While white button mushrooms still provide valuable nutrients, expanding beyond the standard supermarket variety can significantly increase the diversity of beneficial compounds consumed. Varieties such as shiitake, oyster and maitake mushrooms contain higher concentrations of beta-glucans, naturally occurring compounds that have been studied for their role in supporting healthy immune function and cellular defence pathways.

Mushrooms are also one of the richest dietary sources of ergothioneine, a powerful antioxidant that researchers are increasingly interested in for healthy ageing and cellular protection.

One of the simplest ways to increase mushroom intake is to include a variety of types throughout the week rather than relying on a single variety. Mushrooms can be added to soups, stir-fries, omelettes, slow-cooked meals or finely chopped into mince-based dishes.

Light cooking may improve the availability of certain nutrients by breaking down mushroom cell walls, making many of their beneficial compounds easier to access during digestion.

Tomatoes

Star Compound: Lycopene

Tomatoes are the richest dietary source of lycopene, a bright red carotenoid responsible for their vibrant colour.

Lycopene has attracted significant research interest for its antioxidant activity and has been particularly studied in relation to prostate health. While no single food can prevent cancer, higher intakes of lycopene-rich foods have been associated with a lower risk of prostate cancer in a number of observational studies.

One of the most interesting aspects of lycopene is that, unlike some nutrients, it becomes more available after cooking. Heat helps break down plant cell walls, making lycopene easier to absorb during digestion. This means that tomato paste, passata and slow-cooked tomato sauces often provide more bioavailable lycopene than fresh tomatoes alone. In fact, a single tablespoon of tomato paste can contain several times more lycopene than a whole fresh tomato.

Lycopene absorption also increases when consumed alongside fat, making tomatoes and extra virgin olive oil a particularly delicious and beneficial pairing. This may be one reason traditional Mediterranean diets, rich in both tomatoes and olive oil, continue to attract attention in longevity and chronic disease research.

An easy way to increase lycopene intake is to regularly include tomato paste in soups, casseroles, curries, slow-cooked meats and pasta sauces. It is also a wonderful flavour enhancer. I often add a spoonful to soups, including pumpkin soup, for extra richness and depth of flavour.

When available, choose tomato paste and passata in glass jars rather than cans. Tomatoes are naturally acidic, and glass helps reduce unnecessary contact with can linings while preserving flavour and quality.

The Takeaway

While it is tempting to search for a single superfood as a "cure-all", the real power lies in diversity and consistency. Different foods provide different protective compounds, each supporting the body's defence systems in unique ways.

Aim to regularly include a variety of colourful vegetables, herbs, spices, teas and healthy fats. Small daily habits, repeated over years and decades, are where the greatest gains are likely to be found.

Sammy's Meal of the Week: Chicken and Leek Pie

Leeks belong to the allium family alongside garlic, onions and shallots, providing many of the same sulphur-containing compounds discussed in this article. They are also rich in prebiotic fibres that help feed beneficial gut bacteria, supporting gut health, immunity and overall wellbeing. Yet another reason to enjoy a generous serving of our chicken and leek pie.

Further Watching

If this topic has sparked your interest, the following documentaries and series provide thoughtful insights into food, health and longevity.

Cooked

Based on the work of Michael Pollan, this four-part documentary explores how traditional cooking methods shape our food, health and culture. It is a powerful reminder that food is far more than a collection of nutrients and that how we prepare food matters just as much as what we eat.

Live to 100: Secrets of the Blue Zones

This series explores regions of the world where people regularly live long and healthy lives. While the diets vary considerably between these populations, common themes emerge, including whole foods, regular movement, strong social connections, a sense of purpose and relatively low consumption of ultra-processed foods. It serves as a reminder that longevity is rarely explained by a single food or dietary pattern.

Hack Your Health: The Secrets of Your Gut

A fascinating introduction to the human microbiome and the ways food choices influence the trillions of microbes that call our bodies home. It highlights the growing understanding of the connection between gut health, immunity and overall wellbeing.

The Biggest Little Farm

Not a nutrition documentary, but an inspiring look at regenerative farming, biodiversity and the relationship between healthy ecosystems and healthy food systems. It offers a wonderful perspective on where our food comes from and the importance of working with nature rather than against it.

References

World Cancer Research Fund & American Institute for Cancer Research. Diet, Nutrition, Physical Activity and Cancer: A Global Perspective.

National Cancer Institute. Cruciferous Vegetables and Cancer Prevention Fact Sheet.

National Cancer Institute. Garlic and Cancer Prevention Fact Sheet.

Estruch R, et al. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet. New England Journal of Medicine. 2018.

Boehm K, et al. Green Tea (Camellia sinensis) for the Prevention of Cancer. Cochrane Database of Systematic Reviews.

Chen P, et al. Lycopene and Risk of Prostate Cancer: A Systematic Review and Meta-analysis.

Robinson J. Eating on the Wild Side: The Missing Link to Optimum Health. Little, Brown and Company, 2013.