reprinted from the ABC website
Four plant-based foods to eat every week (and why science suggests they're good for you)
As a
laureate professor in nutrition and dietetics people often ask — what do you
eat?
Plant-based
foods are good sources of healthy nutrients. These include different types of
dietary fibre, vitamins, minerals, and a range of phytonutrients, which plants
produce to help them grow or protect them from pathogens and pests.
A review of
12 studies with more than 500,000 people who were followed for up to 25 years.
It found those who ate the most plant foods were less likely to die from any
cause over follow-up time periods that varied across the studies from five to
25 years, compared to those who ate the least.
Here are
four versatile and tasty plant foods I have on my weekly grocery list, and the
research showing why they're good for you.
1. Tomatoes
Tomatoes are
a berry fruit (not a vegetable). They're rich in vitamin C and lycopene,
which is a carotenoid. Carotenoids are pigments produced by plants and give
vegetables their bright colours.
A review asked
people to consume tomato products equivalent to 1 to 1.5 large tomatoes or 1 to
1.5 cups of tomato juice daily for about six weeks.
The
researchers found people who did this had reduced blood levels of triglycerides
as well as lower total and "bad" cholesterol levels, compared to
those who didn't have any tomatoes.
These people
also had increased levels of "good cholesterol".
Researchers
found consuming any tomato products led to a large decrease in systolic blood
pressure (the first number that measures the pressure at which the heart pumps
blood).
However,
there was no effect on the diastolic pressure (the second number which is the
pressure in the heart when it relaxes).
In the group
who had high blood pressure to begin with, both systolic and diastolic blood
pressure decreased after eating tomato products compared to placebos.
A review included
a total of 260,000 men and found those with the highest intakes of cooked
tomatoes, tomato sauces and tomato-based foods (equivalent to around one cup
per week) had a 15-20 per cent lower risk of developing prostate cancer
compared to those with the lowest tomato intakes. Keep in mind correlation
doesn't necessarily mean causation, though.
Recipe tips
Keep canned
tomatoes in the cupboard and add to pasta sauce, casseroles and soup. Make your
own sauce by roasting tomatoes and red capsicum with a splash of olive oil and
balsamic vinegar, then puree with a spoon of chilli paste or herbs of your
choice. Keep in the fridge.
2. Pumpkin
Pumpkin is
rich in beta-carotene, which is also a carotenoid (plant pigment). It gets
converted into vitamin A in the body and is used in the production of
antibodies. It's also needed to maintain the integrity of cells in eyes, skin,
lungs and the gut.
A review looked
at associations between what people ate, blood concentrations of beta-carotene and
health outcomes.
People who
had the highest intakes of foods rich in beta-carotene (such as pumpkin,
carrots, sweet potato and leafy greens) had an 8 to 19 per cent lower relative
risk of having coronary heart disease, stroke, or dying from any cause in
studies over 10 years or more compared to those with the lowest intakes.
3. Mushrooms
Mushrooms
are rich in nutrients with strong antioxidant properties.
The body's
usual processes create oxidative stresss, which generates "free
radicals". These are small particles that damage cells walls and cause the
cells to die.
If these
aren't neutralised by antioxidants, they can trigger inflammation, contribute
to ageing and development of some cancers.
A review found
people who ate the most mushrooms had a 34 per cent lower risk of developing
any type of cancer compared to those with lowest intakes. For breast cancer,
the risk was 35 per cent lower. Though, again, correlation doesn't necessarily
mean causation.
Across the
studies, a high mushroom intake was equivalent to eating a button mushroom a
day (roughly 18 grams).
4. Oats
A review tested
the effects on blood sugar and insulin levels from eating intact oat kernels,
thick rolled oats or quick rolled oats compared to refined grains.
These found
eating intact oat kernels and thick rolled oats led to significant reductions
in blood glucose and insulin responses, but not after eating quick rolled oats.
This is
likely due to the longer time it takes for your body to digest and absorb the
less-processed oats. So it's better to eat whole grain oats, called groats, or
rolled oats rather then quick rolled oats.
Oats are a
good sources of beta-glucan, a soluble fibre shown to help lower blood
cholesterol levels.
Where people
were fed a special diet containing about 3.5 grams of oat beta-glucan a day,
"bad" cholesterol levels were significantly lower compared with
control groups.
Oats showed
a small, but important, drop in blood pressure.
