Clare Collins: Five healthy foods to put in your supermarket trolley

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If you eat to improve your health, here are five foods to put in your supermarket trolley every week. All pack a proven punch if you have them regularly.

1. Oats
Oats are a wholegrain cereal usually eaten for breakfast as porridge or in muesli. They have more soluble fibre than other grains. A soluble fibre found in the outer endosperm cell wall of this cereal known as beta-glucan reduces absorption of cholesterol in the small intestine. Eating enough oats so you get around 3g of beta-glucan daily reduces your total cholesterol and LDL (bad) cholesterol in people with high and normal cholesterol.

Clearly, oats for breakfast are a must. And there's a bonus - they're cheap.

2. Salmon
Salmon is an unusual fish because it's so high in fat; at about 13g of fat per 100g, it has double the fat content of lean steak. But put it on your menu every week anyway because it contains polyunsaturated fatty acids called omega-3s (1.7g per 100g fish), which are components of every cell membrane in your body.

A review of 11 placebo-controlled, double-blind randomised trials, with 15,348 patients who had heart disease, measured the impact of taking 1g of omega-3s daily for at least a year. It found significant protective effects on cardiac death rates, sudden death and heart attacks, though there was no protective effect for all-cause mortality or stroke.

3. Tea
We all know that sharing a cuppa is a great way to feel better. A 2013 review published in the American Journal of Clinical Nutrition found drinking tea improves attention and alertness, while studies suggest it's associated with better cognitive function in the elderly.

Tea constituents thought to have neuro-protective effects include L-theanine, caffeine and catechins.

The Cochrane review on prevention of heart disease found drinking black and green teas led to significant reductions in LDL cholesterol and blood pressure. So, put the kettle on and drink up.

4. Soy foods
A range of health benefits have been attributed to soy foods, although not all the promises hold up to scientific scrutiny.

A review of soy products containing a compound called isoflavones evaluated the impact of soy protein on heart disease risk. In a meta-analysis of 17 randomised trials researchers found a small but significant improvement in blood flow of 0.72 per cent in studies using soy foods, such as soy milk, pasta, soya beans or flour for four to 24 weeks.

The biggest pay-off is their fibre and protein content. They are low in saturated fat, contain some omega 3s and are a good source of folate, thiamin, riboflavin, iron, zinc and magnesium.

Supermarkets carry a range from soy milk, cheese and yoghurt to canned or dried soy beans, tofu, fresh beans, soy "meats" and textured vegetable protein.

5. Vegetables and fruit
Vegetables and fruit can help ward off type 2 diabetes. A 2012 meta-analysis of five studies involving over 179,000 people found a 7 per cent lower risk ratio of developing type 2 diabetes in those with the highest fruit and vegetable intakes compared to the lowest.

The relationship was strongest for green leafy vegetables (bok choy, spinach, cabbage, choy sum, all lettuce varieties, rocket, broccoli, silverbeet, watercress).

The most protective fruit, in descending order were blueberries, prunes, grapes and raisins, apples and pears, bananas and grapefruit.

Clare Collins is Professor in Nutrition and Dietetics at the University of Newcastle