Nobody needs nutritional supplements per se, as supplements do just that, i.e. supplement. And despite what marketing would have you believe, even bodybuilders and strength athletes do not need supplements to make gains, not even the protein powders, which are the most fundamental of all bodybuilding supplements. However, supplements can make achieving goals considerably easier and could speed gains up. Indeed, from as early as the 1950s and 60s egg white powder was being used to help early bodybuilders improve their intake.
There a number of bodybuilders and strength trainers whose only supplement is whey protein powder, and there are a notable number who choose not to use any supplements at all. Their diet is based around good quality food high in protein and carbohydrate, and lots of it!
The key to healthy quality muscle gain is to eat big and eat consistently throughout the day following a structured meal plan. Aim to eat six or seven smaller meals / snacks, rather than three big meals. All meals and snacks should include plenty of high protein food choices, like lean meat, chicken, fish, eggs and milk; high fibre complex carbs like cereals, bread, pasta, rice and potatoes; fruit and vegetable as well as nuts, seeds and pluses and sources of essential fats. Meal timing is also important - spread the meals regularly through the day, and especially important is to eat good amounts of protein and carbs after training.
Here's a sample meal plan for a single day for someone wanting to bulk up and gain muscle without the use of any nutritional supplements:
All the meal plans are merely a guide and must not be stuck to rigidly! You must eat a variety of different meats / fish / alternatives, complex carbohydrates, fruit and vegetables every day, and drink plenty of water. Adapt the plan to suit your own needs according to your results in order to keep the gains coming and body fat down. Varying portions from day to day, along with hard training will help maximise gains.