Making a few healthy tweaks to our diets can change how we feel for the better – but expensive and exotic superfoods can feel inaccessible. The good news is that we don't need rare or costly ingredients to make a real difference; with the help of a registered nutritionist, we've uncovered the game-changing everyday foods that can turbo-charge your meals. Eating well could be far easier (and cheaper) than you thought.

Click or scroll through our gallery to discover 25 health-boosting foods everyone should add to their diet.

It may be healthy eating 101, but you can't beat an apple for a wholesome snack on the go. "Yes, they're common and basic, but apples are really great for us," says registered nutritionist Anna Mapson. "The pectin they contain is a very good fibre to help with digestion. Reddish apples in particular contain quercetin, which is helpful for people with allergies as it helps modulate the immune system." Eat yours raw with the skin on to bag maximum nutrients – and remember that apples are also great paired with proteins like nut butter or cheese for a balanced snack.

Great news for guacamole fans: avocados make a solid healthy addition to your plate. '"They're high in monounsaturated fats, which are very good for managing your cholesterol," says Anna. "They're also a good source of vitamin E, which is good for your skin. They're very good for you." If you're lucky enough to live in a country that produces avocados, they're a fabulous choice; if not, balance them with nuts and seeds to limit your environmental impact.

This brightly coloured vegetable is packed with anti-inflammatory compounds called polyphenols, which help reduce our risk of disease and cell damage – so working them into your diet is always a good idea. It's easy, too; sweet, vinegary beets are perfect in salads, while the earthy raw root can be grated into slaws, tomato sauce or grain-based salads. "Beetroot is really good for cardiovascular health," says Anna. "Athletes drink beetroot juice because the nitric oxide helps transport oxygen around the body."

Carbs have come in for a lot of criticism over the years, but as an essential source of energy they do much to fuel our brains and bodies. The key is to find an option that packs extra fibre, vitamins and minerals alongside natural sugars – and that's where cheap and easy-to-cook wholegrain rice comes in. Swap white rice for brown, and soak it overnight whenever possible to cut the cooking time. It's worth the effort; research suggests that the compounds in brown rice can protect our cells from the damage that causes disease.

If you're immune to the charms of a smooth pâté or seared liver straight from the barbecue, consider this: these rich and delicious nuggets of offal are so high in vitamin A and iron that they're practically supplements (a single serving will give you 100% of your recommended iron). Despite this, however, even the highest-welfare liver is one of the cheapest forms of meat you can buy. True gourmets pre-soak their liver in milk before cooking to remove any bitter flavours.

If you like your nutritional needs to take care of themselves, eggs are a no-brainer. These perfectly packaged portions of protein carry all nine of the essential amino acids our bodies need to grow and repair themselves, plus a host of important vitamins. Getting the best from eggs is also incredibly easy; their nutrients are easily absorbed by our bodies, so eating yours boiled with toast, whipped into a fluffy omelette or fried and served atop a spicy bibimbap will be a quick route to a nutritional boost.

Medicinal herbs offer us a double whammy: great flavour and noticeable impacts on our health. Whether it's parsley's high vitamin C load (great for our immune system), coriander's calming effect on brain activity or the enzymes in basil (proven to slow down the progression of Alzheimer's), nearly every herb has a positive effect on our health. To maximise the benefits to your body, make sure to chop and change the herbs you add to meals, rather than sticking to a single favourite.

What would our ancestors have given for a year-round supply of seasonal berries? Thanks to the magic of the deep-freeze, we can dip into nutrient-rich reserves of blueberries, blackberries and raspberries whenever we make a smoothie, yogurt bowl or summer dessert. The key to berries' impact on our health is a high load of antioxidants: a category of plant chemicals that help prevent heart disease and high blood pressure.

Not only is garlic fundamental to some of the world's most delicious dishes, but it also has a health-boosting effect on those who eat it regularly. Research has proven that eating garlic protects our hearts as we age and can guard against osteoarthritis – plus, it has potent antibacterial qualities. One study suggests that cloves that have started sprouting may be particularly good for heart health, while pre-chopped jars of garlic are less nutritious than fresh. Looking for a way to counteract garlic breath? Just enjoy a glass of milk alongside your gorgeously garlicky dishes.

Delicious and ridiculously easy to grow (they're considered a weed at many public allotments), this root vegetable is sweet, smoky and supercharged with one particular nutrient. "Jerusalem artichokes are very high in prebiotic fibre, which feeds our good gut bacteria," says Anna. Onions, garlic, leeks and asparagus are other prebiotic vegetables, but knobbly 'sunchokes' really are worth learning to love. You could try mashing the cooked tubers into potatoes, blending them into soups or serving them as a simple side dish.

Kale is a really solid ally in your quest for better health – and finely chopped ribbons are easily worked into any soup, stew, risotto, or pasta dish. "All the cruciferous vegetables are good because they contain lots of fibre and sulforaphane, which is helpful for detoxing because it supports the liver," says Anna. "But kale and broccoli are more easily digested than cauliflower and Brussels sprouts, so cause people less gas." Keep some kale in your fridge, and you've always got a healthy green on standby.

We've all heard that Omega-3 fatty acids are essential to good health, but most of us still don't get enough into our diets. That's why nutritionists like Anna always recommend we eat more fish. "Omega-3 is good for skin health, memory, mood and concentration, and all oily fish are good sources," she says. "But being bigger and less bony than sardines, mackerel is easier to get into your diet." Mash yogurt into smoked strips for a wholesome dip, spread the tinned fish across wholegrain toast or pop fresh fillets into the frying pan to get mackerel on your plate in minutes.

Packed with gut-friendly live bacteria, this sour drink is potent enough that even the occasional tot is enough for a real health boost. "It's got more live cultures in it than yogurt, as well as calcium, so it's good for adding diversity to the community of bacteria collected in your large intestine," says Anna. "You can easily make it at home too, so it doesn't need to be expensive." Anna recommends water kefir or kombucha as gut-friendly alternatives for anyone avoiding dairy.

Edible fungi have been having a real moment thanks to their handy habit of bringing meat-like flavours and textures to plant-based meals. Of course, you don't have to be vegan to benefit from putting mushrooms in the middle of your menu. Each species, from shiitake to portobello, has a different vitamin and microbial profile that benefits our gut health, immune function and cholesterol – and much besides. American research has even linked high mushroom consumption with a lowered risk of cancer. 

Packed with vitamins, minerals and some Omega-3s, all shellfish are good sources of lean protein and micronutrients. The added benefits with mussels are cost and convenience, which make a big difference when trying to make healthier habits stick. They're widely (and sustainably) farmed, which makes them cheaper and more easily available than other choices. They're also really easy to add into your diet; chilled vacuum packs of pre-cooked mussels can be reheated in minutes, so they make a great quick meal option.

From porridge and smoothies to biscuits and breads, this humble store-cupboard staple deserves a big place in your daily routine. "Oats are high in a special fibre called beta-glucan, which has been proven to soak up cholesterol," says Anna. They help with our digestive tract too, making life more comfortable for anyone who experiences problem bowel movements. "I often recommend oats to my clients with IBS – they're cheap, tasty and easy to use. If cooking oats doesn't fit your schedule, just soak them overnight."

"Olive oil is a big part of the Mediterranean diet, which has been proven healthy in lots of studies. It helps because it contains good fats – monounsaturated fats – instead of the saturated fat found in, for example, butter." As poor harvests have made olive oil increasingly expensive, Anna also recommends cold-pressed seed oils. "The nutrient profiles are not that different, so they're also good for heart health and avoiding high blood pressure or strokes."

As we've heard, getting variety into our diet is as important as the individual ingredients that contribute to it – so if sea vegetables aren't already a regular part of your intake, consider adding them in. Why? Seaweeds are high in fibre, an essential nutrient most people's diets lack, as well as a dazzling abundance of essential minerals that keep us in good health. They're also easy to enjoy: use kombu strips in soups or stocks, sprinkle sliced nori sheets over rice bowls or stir wakame flakes through noodles.

"Any seed is good for us, but having a diverse mix is even better – they'll give us zinc for our immune system, additional fibre and some good fats," says Anna. If eating seeds raw feels a bit like bird food, try dry frying them with a little soy sauce or tamari until they're savoury and crunchy. Then, you can eat them on their own or sprinkle them over salads, soups or stir fries. Alternatively, add plain seeds to your granola or yogurt bowl for extra protein and fibre.

The potent nutrients found in the roots, seeds and bark of plants have been captured since ancient times, adding not just vibrant flavours but also medicinal impacts to our food. "These antioxidants are concentrated when they're dried and ground," says Anna, "so even a small amount is good." A good goal is to get to 30 plant-based foods a week, with Anna reckoning each spice might constitute a quarter 'point'. Be sure to keep your spices out of sunlight in a dark, cool cupboard to preserve their power.

A simple tip for finding the most nutritious fruit and vegetables is to seek out strong colours – and these bright orange root vegetables are a perfect example. "Sweet potatoes are good for beta carotene, which our bodies convert to vitamin A," says Anna. "It's very good for your immune system and eyesight, and every cell needs it to regenerate." Other orange fruits and vegetables (squashes, carrots and oranges, for example) contain beta carotene too, which helps fight the cell damage that causes many diseases.

Canned beans, lentils, chickpeas and split peas are the workhorses that can bring a quick cupboard meal together, and they add a volume of fibre you can really feel good about. Cheap, filling and super convenient, they can bulk up anything from beef patties to jackfruit curries. They're also delicious on their own as a speedy dahl, dressed as a salad or eaten as a side dish. "Adding these different types of fibre to our diets is great for our gut bacteria," says Anna. "The more varied, the better."

Want a healthy protein that lives long in your fridge and is brilliantly versatile in meals? Turn up your tofu intake, adding it to stacked sandwiches, kebabs or tacos. "It might sound basic," says Anna, "but tofu is a really good protein, especially for people following plant-based diets, and the watery solution it's sometimes stored in contains calcium. It also has good amounts of protein and fibre per portion, and that's not true of many plant-based options."

Fresh, canned, bottled, sun-dried or puréed, tomatoes are a convenient addition to any hasty meal or spur-of-the-moment snack – and they're so common, it's easy to forget they have an impressive nutritional profile. They're high in the vitamins and fibre you'd expect from a bright fruit, but also lycopene – a nutrient that can protect us from everything from sunburn to heart disease. Lycopene becomes easier for us to absorb when tomatoes are cooked, making tinned tomatoes or jarred sauces a great alternative to fresh.

Containing vitamins, minerals, fibre and even Omega-3s, walnuts have been found by researchers to lower cholesterol, regulate appetite and lower blood pressure – not bad going for a snack that will happily live in your desk drawer or rucksack. "They're also very good for your gut health and, along with pecans, they tend to be easier to digest than some other nuts, so produce less gas," says Anna. Try tossing chopped walnuts over leafy salads or granola, or stir them through pasta dishes for an instant nutrient boost.

Now discover our A-Z of ingredient pairings that could give your health a boost