Kakadu Plum Seed: What’s Inside the Kernel, and Growing the Tree

By Darren McArthur, Real McArthur, an Australian family business making natural products for over 25 years · Published 25 September 2026 · Last updated 30 September 2026 · Sourced from published studies

Our Kakadu plum, lab tested: 121mg of natural vitamin C in every gram, 60mg in every capsule, against an adult need of 45mg a day. Gram for gram, 240 times the vitamin C of a fresh orange.

Yes, the Kakadu plum seed kernel is edible, and it is surprisingly nutritious. A 2018 peer-reviewed study measured the dried kernel at 32% protein, 35% fat and 21% fibre, with 421mg of magnesium, 539mg of calcium and 6.0mg of zinc per 100g, and concluded it “could be a new protein source.” The seed holds more than the fruit in 7 of 8 minerals. This page covers what is inside the kernel, how it compares, and how to grow a Kakadu plum tree.

The Kakadu plum is one fruit with two completely different nutritional stories — and most supplements tell only one of them.

The story everyone knows: the fruit flesh holds the highest recorded natural vitamin C of any fruit. Our independently lab-tested powder measures 12,100mg per 100g: gram for gram, 240 times the vitamin C of a fresh orange, with 60mg in every capsule.

The story almost nobody tells: the seed kernel holds the four minerals the body needs to turn that vitamin C signal into actual collagen.

Most Kakadu plum suppliers remove the seed before they powder the fruit. Some brands market this as a feature: “NO SEED = more Kakadu plum” or “Seed-free!” It is true that removing the seed raises the vitamin C concentration per gram. What it leaves behind is the mineral co-machinery that vitamin C depends on.

Kakadu Plum Capsules — whole fruit and seed, 46 cents each →

The Seed Completes the Collagen Picture

Building collagen in the body is not a single-step process. It requires a set of co-factors working together. Vitamin C activates the synthesis enzymes and signals fibroblasts — the cells in skin and connective tissue — to produce collagen. But vitamin C cannot complete this process alone. It requires four mineral co-factors: iron, zinc, copper and manganese. [1]

These four minerals are the machinery that vitamin C sets in motion. Without them, the signal is sent but the work is not completed.

Here is where each co-factor sits in the two parts of the fruit:

The fruit brings vitamin C and vitamin E. The seed brings iron, zinc, copper and manganese — at levels 1.5 to 10 times higher than the flesh. In a whole fruit capsule, both parts are present. In a de-seeded powder, only the fruit column exists.

Source: DePhillipo NN et al., Orthopaedic Journal of Sports Medicine 2018 (PMC6204628) for the co-factor roles. RIRDC Australian Government Pub. 09/133 (2009) and Akter et al. Foods 2018 (PMC5920425) for the Kakadu plum figures. FSANZ approved wording: “Vitamin C contributes to normal collagen formation for the normal function of skin.” [1][2][3]

What Is the Kakadu Plum Seed Kernel?

The seed is the woody structure inside the fruit. Inside the seed is the kernel — the inner core that holds the nutritional value. The kernel makes up about 8% of the seed’s weight. In practical terms: every 100 kg of fruit produces about 22 kg of seed, and the kernel is the dense interior once the shell is removed.

The seed coat — the outer shell — has very little nutritional value: about 0.1 to 0.3g of phenolics per 100g and minimal tannins. [4] The goodness is in the kernel. When we say “whole fruit including seed kernel,” that is what we mean.

Full Nutritional Profile of the Seed Kernel

The kernel was measured in a dedicated 2018 peer-reviewed study (Akter et al., Foods, PMC5920425), which concluded the kernel “could be a new protein source.” The Australian Government’s 2009 study measured the fruit, which gives the fruit figures we compare it against.

Macronutrients (per 100g dried kernel)

• Protein: 32% — above chickpeas (19%), above lentils (25%), approaching soybeans (36%). The protein content also means magnesium naturally bonds to amino acid side chains in the food matrix — the same mechanism chelated supplements like magnesium glycinate try to replicate synthetically.
• Fat: 35% — about 80% unsaturated
• Fibre: 21%
• Energy: 2,065 kJ per 100g

The Fat Profile

• Linoleic acid (omega-6): 50.2% of the fat — the polyunsaturated fat found in sunflower and flaxseed oils
• Oleic acid: 29.2% of the fat — the same monounsaturated fat that accounts for about 73% of olive oil and about 65% of avocado. Present in an Australian seed most people have never heard of.
• Palmitic acid: 12.0% — saturated, same family as palm oil and butter
• Stearic acid: 7.2% — saturated, found in dark chocolate and beef fat
• About 4 in every 5 grams of fat in the kernel is unsaturated

Minerals (per 100g dried kernel)

Heavy metals were measured and found low: lead 0.013mg per 100g; arsenic, mercury and cadmium each below 0.01mg per 100g. [2]

Why Nearly Every Supplier Removes the Seed

The commercial logic is simple. Kakadu plum powder has been sold as a vitamin C ingredient since the 1990s, and the vitamin C lives in the fruit flesh, not the seed. Suppliers who chase vitamin C per gram remove the seed, because including it dilutes the number. That argument is correct on its own terms: a de-seeded powder does have more vitamin C per gram.

What it doesn’t address is what leaves with the seed: everything in the tables above. The four collagen mineral helpers, the calcium and magnesium, the protein, and a fat profile mostly made of the same unsaturated fats found in olive oil and avocado. Most processing decisions in the industry were made when the only question anyone asked about the fruit was how much vitamin C it had.

Oxalate — Does the Seed Add More?

Whole fruit including seed measured 2,633 to 2,717mg of oxalate per 100g dried. Puree with most seeds removed measured 2,466 to 2,573mg. [5] The seeds barely change the oxalate level.

For context: a 500mg capsule of whole fruit powder contains about 7 to 14mg of oxalate — about the same as one cup of raspberries. Cooked spinach at the same serve size contains around 35 to 70 times more.

If you have a history of kidney stones, speak to your health professional before adding any high-vitamin C food to your routine, as the body converts some vitamin C to oxalate.

Growing a Kakadu Plum Tree

Yes, you can grow a Kakadu plum tree: it needs a frost-free tropical climate, full sun and very good drainage, and a grafted tree fruits in 1 to 2 years. Kakadu plum (Terminalia ferdinandiana) is a tropical tree native to northern Australia. It grows along the coast from Broome through the Kimberley and the western Top End to Arnhem Land and as far east as Limmen National Park, and across the Gulf in far north Queensland on Cape York, in dry creek beds, coastal vine thickets, sand dunes and sandplains, on red sand, sandy clay, sandstone, ironstone and granite.[6][7]

• Size: usually 4 to 10m tall, up to 14m in the wild, and it can be kept in a large pot of 50 litres or more.[7][8]
• Climate: tropical, with no frost and temperatures staying above 5°C.[8]
• Position: full sun, very good drainage, and moderate to low water once established. It’s waterwise and cyclone-resistant, and is often planted as a shade or screening tree.[8][9]
• Fruit: the tree pollinates itself. Small, creamy-white, perfumed flowers open in spikes, and the fruit ripens from March to May in the Northern Territory and January to February in the Kimberley.[6][8]
• Grafted or seed-grown: grafted trees, usually on a hardier Terminalia catappa rootstock, fruit much sooner than trees grown from seed.[8]

Specialist tropical and native plant nurseries sell grafted Kakadu plum trees. If you live south of the tropics, a pot you can move to shelter is the safest way to keep one frost-free.

How Our Capsules Use Whole Fruit

Our Kakadu plum capsules use whole fruit powder — fruit and seed kernel ground together to the same fine, consistent powder. The seed kernel is processed to the same standard as the fruit flesh. That costs more and takes more time.

We do it because the numbers are worth it. The published data proves it: the seed holds more than the fruit in 7 of 8 minerals, including the four mineral co-factors that complete the collagen story the vitamin C starts. The whole fruit, seed and all, gives you more than either part alone.

Kakadu Plum Capsules — whole fruit and seed, 140 capsules, 46 cents each →

For the full science on vitamin C and collagen, see our collagen page. For the full magnesium comparison including serving sizes, see our magnesium page. For the 11 named tannins in the fruit, plus terminalagin, see our tannins page.

Every nutrient in the fruit, one at a time: Kakadu plum nutrition → · What is Kakadu plum? · Kakadu plum vitamin C · antioxidants · vitamin E

Frequently Asked Questions

What is the Kakadu plum seed?

The Kakadu plum seed is the woody stone inside the fruit. Its edible kernel is about 8% of the seed’s weight, and every 100kg of fruit gives about 22kg of seed.

Can you eat Kakadu plum seeds?

Yes, the seed kernel is edible. A 2018 peer-reviewed study measured its full nutrition and found it low in heavy metals, at 32% protein, 35% fat and 21% fibre.

Why do most Kakadu plum powders not contain the seed?

Because removing the seed raises the vitamin C per gram, since the vitamin C is in the fruit flesh. The trade-off is that the seed holds more than the fruit in 7 of 8 minerals, including iron, zinc, copper and manganese.

What nutrients are in the Kakadu plum seed kernel?

Per 100g dried kernel (Akter et al., Foods 2018): Protein 32%, Fat 35% (about 80% unsaturated), Fibre 21%. Minerals: Phosphorus 873mg, Potassium 669mg, Calcium 539mg, Magnesium 421mg, Iron 6.1mg, Zinc 6.0mg, Manganese 9.1mg, Copper 2.5mg, Sodium 120mg. The dominant fats are linoleic acid (omega-6, 50%) and oleic acid (29%) — the same monounsaturated fat that accounts for most of olive oil.

What is the connection between the Kakadu plum seed and collagen?

Vitamin C from the fruit switches on collagen-building, and the four mineral helpers it needs, iron, zinc, copper and manganese, are concentrated in the seed. A whole fruit capsule carries both.

Is the Kakadu plum seed high in protein?

Yes. At 32% protein by weight, the dried kernel sits above chickpeas (about 19%) and lentils (about 25%) and close to soybeans (about 36%).

Is whole fruit Kakadu plum powder better than de-seeded?

They are different products with different nutrition. De-seeded powder optimises for vitamin C per gram: removing the seed raises the concentration. Whole fruit powder includes the seed kernel’s minerals, protein and fatty acids alongside the fruit’s vitamin C, tannins and polyphenols. If vitamin C is the only goal, de-seeded is more efficient. If you want the complete nutritional profile of the plant — including the mineral co-factors for collagen synthesis alongside the vitamin C — whole fruit includes all of it. That is why we keep the seed: the whole fruit, seed and all, gives you more than either part alone.

Can Kakadu plums be eaten by humans?

Yes. Kakadu plum has been eaten as a bush food by Aboriginal people for thousands of years, raw from the tree, and today it’s eaten fresh, frozen, or dried into powder. The seed kernel inside is edible too, and measured at 32% protein.

Can I buy Kakadu plum plant seeds?

Kakadu plum seeds are sold by some native seed and plant suppliers, but most people growing for fruit buy a grafted tree instead, because grafted trees fruit in 1 to 2 years. Check your state’s rules first: Western Australia and Tasmania restrict seeds brought in from other states.

Where can I buy a Kakadu plum plant?

Specialist tropical and native plant nurseries sell Kakadu plum trees, including grafted ones. The tree needs a tropical, frost-free climate, so outside the tropics grow it in a large pot you can move to shelter.

What are the side effects of Kakadu plum?

Kakadu plum is high in oxalate, like spinach, beetroot and rhubarb. A 500mg capsule of whole fruit powder carries about 7 to 14mg of oxalate, about the same as a cup of raspberries. If you have had kidney stones, speak to your health professional before adding any high-vitamin C food.

References

1. DePhillipo NN et al. Efficacy of Vitamin C Supplementation on Collagen Synthesis and Oxidative Stress After Musculoskeletal Injuries. Orthopaedic Journal of Sports Medicine, 2018. PMC6204628.
2. Akter S et al. Chemical and Nutritional Composition of Kakadu Plum Kernels. Foods, 2018. PMC5920425.
3. Konczak I et al. Health Benefits of Australian Native Foods. RIRDC Australian Government Pub. No. 09/133, Sept 2009.
4. Akter S et al. Antioxidant Rich Extracts of Terminalia ferdinandiana Inhibit the Growth of Foodborne Bacteria. Foods, 2019. PMC6724055. (Seed coat phenolic data.)
5. Williams DJ et al. Organic acids in Kakadu plum. Food Research International, 2016. (Oxalate data.)
6. Parks Australia, Kakadu National Park: Kakadu plum.
7. FloraBase, Western Australian Government: Terminalia ferdinandiana.
8. Ross Creek Tropicals: Kakadu plum tree growing notes.
9. Territory Native Plants: Terminalia ferdinandiana.
10. USDA FoodData Central, for the everyday food comparisons (chickpeas, lentils, soybeans, banana, milk, beef, spinach, olive oil and avocado fats).

For the plant protein comparison — where the seed’s 32% sits against chickpeas, lentils, soy, and hemp — see our plant based protein page.

Our products are food, not therapeutic goods, and are not intended to diagnose, treat, cure or prevent any disease or condition.