Yes it's true. You need to understand that lenders treat investment properties differently than residential properties. For all residential mortgage loans, there is a clause in the documents that states the buyer will move into the home within 60 days after closing. If the buyer fails to do this, the lender will take legal action. Because of this clause, lenders provide low down payment options and low interest rates and fees.
For all investment mortgage loans, lenders know that if anything happens to you in the future (job loss, divorce, death, medical situation, etc.) that you have the ability to default on paying the loan or make payments late. Since this is not your primary residence, you could also walk away. Because of this, lenders want more cash upfront - just in case. Therefore, down payment requirements are higher (20% or more, interest rates are higher and fees are higher.
If you only have 5% for a down payment, you cannot buy an investment property.