New healthy eating guidelines for school dinners neglect the needs of vegetarian and vegan pupils and aren't necessarily healthy in general, according to vegetarian campaigners.

The guidelines, brought in last month, are to be followed by schools to provide healthier lunches for children.

The guidelines say that schools should provide a vegetarian option every day, but they include no vegetarian or vegan alternatives to some of the major sources of nutrients they recommend.

Vegetarian campaigners are especially concerned that the guidelines recommend sources of protein (dairy) and omega oils (fish) that are unsuitable, unhealthy and uneconomical.

Rosamund Raha, head of information at the Vegan Society, said: "We are disappointed to see that red meat must be available twice a week in primary schools and three times a week in secondary schools, especially as the World Health Organisation and Food Standards Agency agree that meat is not necessary for good health.

"And the guidelines suggest that the only alternative protein source considered acceptable in a packed lunch is a dairy source of protein. We would like to point out that nuts, seeds, pulses and grains can be excellent sources of protein.

"The standards also require a dairy product to be available on a daily basis, when there is strong evidence to show that dairy products are unnecessary and contain a great deal of unhealthy saturated fat."

Campaigners and nutritionists have also expressed concern about the recommendation of fish oil as a source of the essential fatty acid omega 3. One section of the 32-page guidelines clearly encourages schools to serve more oily fish to ensure that children get their intake of omega 3 oils.

The Vegetarian Society said the guidelines should be clearer that fish is not the only source of omega 3.

A spokeswoman for the society, Collette Walsh, said it was "not helpful" to suggest that fish oils were the only way to get omega 3. "Vegetarians do not eat fish, but they can obtain omega 3 easily from a host of healthy alternatives like flaxseed oil, walnuts, and eggs. Feeding all children well is the issue here," she said.

Asked about this, a press officer for the School Food Trust suggested fish oil capsules as a vegetarian source of omega 3 oil, apparently unaware that they are unacceptable to vegetarians.

The Vegetarian Society estimates that at least 6% of schoolchildren are vegetarian. Ms Walsh said: "There are growing numbers of younger vegetarians, and school canteens have a responsibility to be properly informed not just about nutrition in general but vegetarian nutrition too."

A leading nutritionist also claims that the encouragement for schools to serve more oily fish is unsustainable.

Yvonne Bishop-Weston, a member of the British Association on Nutritional Therapy and the vegetarian and vegan consultant for the Food Doctor range of health foods, said: "There is no other significant mention of essential fats other than oily fish or of balancing omega 3 and omega 6. And 5,000 school children in Durham are being plied with fish oils which are an unsustainable solution both financially and environmentally."

The School Food Trust, which is receiving £15m government funding to help the drive to improve school meals, has set up a helpline for schools and parents with questions about the guidelines.

Posing as the parent of a vegan child, a reporter for SocietyGuardian.co.uk called the helpline to ask what the arrangements for vegetarians and vegans were at schools.

Within 24 hours, the trust called back to say the matter was being referred to its nutritionists.

It explained: "There are further discussions going on about this with our nutritionists and the Department for Education and Skills. We're waiting for further advice.

"We've had a few queries like this and we're still waiting for more information. It's a bit of a grey area. You should hear something back from us in the next week or so."

Two weeks later SocietyGuardian.co.uk had still not heard back from the helpline on this matter.

Claudia Cahalane writes on this subject in the November issue of Lifescape magazine