How to eat healthy

We eat food for many reasons: for comfort, as a social event, because we enjoy it and as a source of nutrition. In Australia the government, in collaboration with the National Health & Medical Research Council (NHMRC), set Recommended Daily Intakes (RDIs) for most nutrients. These are the levels of each nutrient we need every day to prevent deficiency and keep us healthy. Recently, these have been updated and significant changes have been made, which will affect dietary recommendations on how we eat. This article is about the new RDIs — what has changed, why and how those changes affect your weekly diet.

Why are nutrients important?

Food supplies you with the building blocks that make up your body. It also provides fuel and the ability to make the enzymes that instigate all the biochemical reactions occurring inside you. It’s from food that you get the protein, carbohydrates, fat, vitamins, minerals and antioxidants that keep you alive and healthy. The way you eat dramatically affects how well your body runs.

Even when you want to do the right thing, it’s still hard to know exactly what to do. What does a balanced diet look like? It can be a challenge. In Australia, the recommended daily intakes (RDIs) are meant to answer a lot of these questions.

Recommended daily intakes (RDIs)

RDIs set specific amounts for each nutrient, showing how much you need on a daily basis. The RDIs were first published in the 1950s and since then, with a few tweaks, have been the accepted levels of each nutrient required to keep us healthy and prevent deficiency. The last set of RDIs was published in 1991.

There is still a lot we don’t know about what nutrients do inside our bodies. However, nutritional knowledge has definitely moved on since the 1950s and in 2006 a new set of RDIs was published. This work forms the basis of all government nutritional advice and guidelines. It’s from the RDIs that food policy is developed and guidelines are set. The RDIs are the basis of the food pyramid, along with government initiatives like the current ‘Go For 2 + 5’ program aimed at encouraging people to eat more fruit and vegetables.

The new RDIs are an interesting bunch. Many levels have increased, only one has significantly decreased and a whole series of new values are included. Moreover, for the first time, these nutrient reference values reflect the role and importance of food and the diet we eat in fighting many of the diseases that are rife in our community.

Changes to some individual RDIs

Advances in the methods of testing for different nutrients at the biochemical and metabolic level have led to changes in the way RDIs are calculated for a number of nutrients, and some of these changes are quite considerable. For example, recent data showing the importance of folate in red blood cell production and lowering homocysteine levels (an amino acid linked to heart disease) suggest the RDI for folate has doubled to 400mcg per day for most people and 600mcg for pregnant women. Calcium levels have increased by about 200mg per day as we now know calcium is lost in sweat.

While most nutrient levels have increased, the RDI for sodium has shrunk from an upper level of 2300mg down to 920mg per day. Increasing concerns about the amount of sodium we consume from salt in Australia, combined with the link between high sodium diets and cardiovascular problems, are driving this level down.

The current RDIs also include daily intake values for a whole range of nutrients that have never been included before, which again reflects the changes and development in nutritional knowledge. For the first time, there are RDIs for omega-3 and omega-6 fats, fibre, water, fluoride, vitamin K, chromium and manganese, to name a few.

Upper levels and ranges

For the first time, the RDIs now include maximum levels for most nutrients, called the Upper Level of Intake (UL). The ULs are the highest safe amount of a particular nutrient that can be consumed each day. While vitamins and minerals occur naturally and are important for our health, it’s not always true that more is better; in fact, over certain levels they can cause serious health problems. While excessive amounts are rare from dietary sources, these ULs are included to prevent such adverse health effects.

In the past, while the RDI varied for different age groups, there was no differentiation between the needs of men and women. This is a problem because men and women have different nutritional requirements. At a basic level, men are generally taller than women and have more muscle mass, so they need more of most nutrients. Other differences exist. For example, women need more iron to make up for the blood lost during menstruation, whereas men need more zinc because of losses in semen. The new figures include a range of values, depending on age and sex. Different recommendations are also included for women who are pregnant and lactating.

Suggested dietary targets

The RDIs are set at a level to prevent deficiency and maintain current good health. However, more and more, we are realising the role diet plays in preventing ill-health in the future. A number of the most common chronic diseases such as diabetes, cardiovascular disease, cancer and macular degeneration have a strong link to diet and for the first time the RDIs reflect this. Many of the nutrients now have a Suggested Dietary Target (SDT) value, as well as an RDI.

It’s this change that’s the most significant. SDTs encouraging you to go beyond the RDI values and eat more of those nutrients that help prevent chronic diseases and keep you healthy in the long term. It’s also an important reflection of the fact that you do have control over your health in the long term.

SDTs have been set for:

• Omega-3 essential fatty acids
• Fibre
• Folate
• Vitamin A and carotenoids
• Vitamin C
• Vitamin E
• Potassium
• Sodium
• Selenium

Some of these SDTs are significantly different from the RDI. For example, while the RDI for omega-3s for a woman is 90mg per day, the SDT is 430mg (and for a man that goes from 160mg to 610mg). The RDI of vitamin A for men is 900mcg, whereas the new SDT encourages 1500mcg, while for women the RDI is 700mcg and the SDT 1220mcg.

How to eat the RDIs and SDTs

When thinking about how to eat according to the new guidelines, it’s important to make a distinction between those foods that are energy-rich but nutrient-poor and others that are nutrient-rich. If you think about a donut, it’s made from white flour, it’s deepfried then coated with a sugar layer or topping. This is a high-energy food with lots of kilojoules, but that’s about it. Compare that to a punnet of blueberries, which is packed full of nutrients: fibre, low-GI carbohydrates, potassium, vitamin C and antioxidant flavonoids. While one donut will give you about 835kJ, for the same amount of energy you could eat almost 300g of nutrient-rich blueberries (about three punnets).

While you are filling up on energy-rich foods, you’re missing out on other, healthier foods. If chocolate is your afternoon snack, it’s probably at the expense of a piece of fruit and a yoghurt. While both will get you through the 3pm slump, the fruit and yoghurt also give you many nutrients towards your daily RDI and SDT targets.

So eating the RDIs and SDTs is about replacing more of those energy-rich foods, such as white bread, chips, lollies, most fast food and chocolate bars, with nutrient-rich foods, such as fruit, vegetables, nuts, fish, lean cuts of meat, legumes and dairy. This doesn’t mean a complete ban on all sweets and treats, but a change to view them as occasional rather than everyday foods. Instead of thinking about what you shouldn’t be eating, try concentrating on getting the foods you do need every day (vegetables, fruit, wholegrain cereals, fish, lean meats, dairy and mono-unsaturated oils) and then add in the other stuff as more occasional treats.

Vegetables: 6-7 servings per day

Before the release of the new RDIs, nutritional guidelines recommended five servings of vegetables each day. However, to get all the RDIs and the SDTs you’ll need to increase this to six or seven servings per day. Also, try to include at least one serving of legumes (lentils, chickpeas etc) and one serving of green vegetables (spinach, silverbeet, rocket, broccoli, cabbage etc) per day. A serving of vegetable corresponds to 1 cup of salad or ½ cup of other vegetables.

This is one of the big changes and is going to be the hardest for most people to incorporate into their daily diets, given that many struggle with the current five-serving recommendation. The reason vegies are so important is they provide potassium and fibre, while many also include carotenes, magnesium, riboflavin, vitamin C and zinc. Without 6-7 servings of vegetables, you will struggle to make the potassium and fibre targets.

To increase your vegetable intake:

• Have ½ carrot and 1 stick of celery cut into sticks with ¼ cup homous as a snack (about 2 servings)
• Include "all salad vegetables" in your sandwich at lunchtime (about 2 servings)
• Have avocado and tomato on your toast in the morning instead of jam (1 tomato = 1 serving)
• Include ½ cup broccoli, ½ cup carrot, as well as a large handful of spinach and ½ cup of tofu in your stirfry in the evening (4 serves)
• Add a large handful of baby spinach and fresh mushrooms to a pre-made tomato-based pasta sauce and serve with a cup of salad (4 serves)