Six per cent of people in need of adult social care feel socially isolated and have little contact with friends, family or neighbours, according a survey from the Health and Social Care Information Centre (HSCIC).
The poll of more than 70,000 people who use social care services in England found that a further 16% of people felt as though they had some social contact but not enough.
A third felt as though the amount of time they spent with others was "adequate" and 44% said they had as much contact as they would want.
David McCullough, chief executive at Royal Voluntary Service, said: "The risk of being isolated from society increases as you get older and it substantially increases for those faced with additional challenges such as poor health and mobility."
"The challenge is to identify the tell-tale signs of isolation and the resulting loneliness, early. Many older people would not identify themselves as being socially isolated or lonely but for those around them, the warning signs are more apparent.
"We would encourage friends, family, carers and neighbours of older people to ensure that their relative or friend remains connected with the community through voluntary sector organisations who can provide vital support through local volunteers.
"The earlier this connection can be made the quicker the effect of loneliness can be lessened or avoided all together."
The HSCIC survey also found that almost one in 10 social service users think that their quality of life is bad.
Three per cent said that their life was "very bad" or "so bad, it could not be worse" and a further 6% said their quality of life was "bad", according to the survey.
The survey related to the year 2013/14 when there were 1,267,000 people receiving adult social services in England.
Care and support minister Norman Lamb said: "In our busy lives it can be easy to forget that thousands of people can often go for days without speaking to the people they care about or even having contact with anyone at all.
"We know that loneliness can have a significant impact on people's health - increasing the risk of heart disease and putting people at greater risk of blood clots and dementia.
"By highlighting areas where social isolation is high, better services and care can be targeted at those who need it most.
"But we can all play our part in making sure that those who are isolated feel part of the community again.
"Volunteering can provide an extra layer of contact and support to help make a real difference to people's lives."