Omega-3 fish oil after 50 in NZ: what it does and how to choose

Fish oil is one of the most-bought supplements for adults over 50 — and one of the most confusing to shop for. The bottles all look similar, the numbers on the back don’t match up, and the prices are all over the place. This guide cuts through it.

I’m Dr Roderick Mulgan, an Auckland GP and the founder of Lifeguard Health. Here’s a straight, evidence-based look at omega-3 for New Zealanders 45 and over: what it does, how much you need, and how to tell a good fish oil from a poor one.

The short version

Fish oil is useful, but the label matters. The benefit comes from two specific omega-3 fats — EPA and DHA — so a “1000mg fish oil” capsule that’s only a small percentage EPA and DHA may give you less than a smaller, more concentrated one. If you already eat oily fish a few times a week, you may be getting plenty. If you don’t, a quality fish oil is a sensible top-up.

What omega-3 supports as we age

The evidence for omega-3 is strongest for the heart and brain, both of which deserve more attention after 50.

• Heart: EPA and DHA support normal heart and circulatory health, which becomes more relevant as cardiovascular risk rises with age.
• Brain: DHA is a major structural fat in the brain, and omega-3 supports normal brain function.
• Joints: omega-3 has anti-inflammatory properties and may support joint comfort, particularly alongside the other foundations of joint health.
• Eyes: DHA is also concentrated in the retina, and omega-3 supports normal vision.

A note on honesty: omega-3 supports these areas of health. It doesn’t prevent heart disease or dementia, and any product claiming it does is overstepping what the science — and the rules — allow.

EPA vs DHA — and why the ratio matters

The two omega-3s do slightly different jobs. EPA is the one most associated with the anti-inflammatory and heart-related effects; DHA is the structural one, important for the brain and eyes. Most good fish oils contain both, and for general healthy ageing a balanced product is fine. The key thing is to look at the actual EPA and DHA figures on the label — that’s the part that’s doing the work — rather than the total “fish oil” number.

How much do you need?

For general health, a combined EPA and DHA intake in the order of 250–500mg a day is a reasonable target for most adults, and that’s achievable with a couple of serves of oily fish a week. Higher intakes are sometimes used for specific reasons, but that’s a conversation for your GP — especially if you take blood-thinning medication, as high-dose fish oil can interact.

How to choose a fish oil

If you decide a supplement is worth it, here’s what separates a good one from a poor one:

• EPA/DHA concentration: check the actual milligrams of EPA and DHA per capsule, not the total oil. Higher concentration means fewer, smaller capsules for the same dose.
• Freshness: fish oil can oxidise (go rancid), which is bad for both effectiveness and taste. A reputable brand, a sensible use-by date and proper storage matter.
• Sustainability: look for credible sourcing — small wild-caught species or a recognised sustainability certification.
• The capsule you’ll actually take: if a fish oil is huge or causes “fishy burps”, you won’t stick with it. Smaller, concentrated or enteric-coated capsules help.

Food first

The best source of omega-3 is oily fish, and New Zealand has some good options — salmon, mackerel, kahawai, trevally and sardines all count. Two to three serves a week will give most people a solid EPA and DHA intake without any supplement at all. The honest position is that if you eat fish regularly, you may not need a fish oil; if you rarely do, that’s where a supplement earns its place.

Where Lifeguard fits

I’ll be straight with you: Lifeguard doesn’t sell a standalone fish oil, so I’m not going to pretend one of our products is your omega-3 source. Use the guidance above to get omega-3 from oily fish or a quality dedicated supplement.

Where our range fits is the rest of your daily foundation. Lifeguard Essentials is our doctor-formulated daily base for adults 45+, and the Lifeguard Bundle pairs it with our other core formulas. For more, see our healthy ageing supplements guide and our companion guide on vitamin D for over-50s in NZ.

A supplement supports good nutrition — it isn’t a substitute for medical care. If you take blood-thinning medication or have a heart condition, talk to your GP before starting a high-dose fish oil.

Frequently asked questions

How much omega-3 should I take over 50?

For general health, a combined EPA and DHA intake of roughly 250–500mg a day suits most adults, which two to three serves of oily fish a week will cover. Higher doses are sometimes used for specific reasons, but check with your GP first — especially if you’re on blood-thinning medication.

What’s the difference between EPA and DHA?

They’re the two main omega-3 fats in fish oil. EPA is most associated with anti-inflammatory and heart-related effects; DHA is a structural fat important for the brain and eyes. A good fish oil contains both — check the actual EPA and DHA figures on the label.

Is fish oil good for joints?

Omega-3 has anti-inflammatory properties and may support joint comfort, particularly alongside the other foundations of joint health. It’s not a treatment for arthritis — if joint pain is persistent, see your GP.

How do I choose a good fish oil in NZ?

Check the EPA/DHA concentration (not just total oil), choose a fresh product from a reputable brand to avoid oxidation, look for sustainable sourcing, and pick a capsule size you’ll actually keep taking. Concentration is what lets you get the dose in fewer, smaller capsules.

Can I get enough omega-3 from food?

Often, yes. Two to three serves of oily fish a week — salmon, mackerel, sardines and similar — gives most people a solid EPA and DHA intake. If you rarely eat fish, that’s when a supplement is worth considering.

Written by Dr Roderick Mulgan, NZ GP and founder of Lifeguard Health. This article is general information, not medical advice. For advice about your own health, see your GP — especially if you take blood-thinning medication.